<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE article  PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "http://dtd.nlm.nih.gov/publishing/3.0/journalpublishing3.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" dtd-version="3.0" xml:lang="en" article-type="research article"><front><journal-meta><journal-id journal-id-type="publisher-id">APM</journal-id><journal-title-group><journal-title>Advances in Pure Mathematics</journal-title></journal-title-group><issn pub-type="epub">2160-0368</issn><publisher><publisher-name>Scientific Research Publishing</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.4236/apm.2016.64019</article-id><article-id pub-id-type="publisher-id">APM-65099</article-id><article-categories><subj-group subj-group-type="heading"><subject>Articles</subject></subj-group><subj-group subj-group-type="Discipline-v2"><subject>Physics&amp;Mathematics</subject></subj-group></article-categories><title-group><article-title>
 
 
  Sums of Squares of Polygonal Numbers
 
</article-title></title-group><contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>.</surname><given-names>Gnanam</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>B.</surname><given-names>Anitha</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref><xref ref-type="corresp" rid="cor1"><sup>*</sup></xref></contrib></contrib-group><aff id="aff1"><addr-line>Department of Mathematics, Government Arts College, Tiruchirappalli, India</addr-line></aff><author-notes><corresp id="cor1">* E-mail:<email>anithamaths2010@gamil.com(BA)</email>;</corresp></author-notes><pub-date pub-type="epub"><day>15</day><month>03</month><year>2016</year></pub-date><volume>06</volume><issue>04</issue><fpage>297</fpage><lpage>301</lpage><history><date date-type="received"><day>6</day>	<month>February</month>	<year>2016</year></date><date date-type="rev-recd"><day>accepted</day>	<month>26</month>	<year>March</year>	</date><date date-type="accepted"><day>29</day>	<month>March</month>	<year>2016</year></date></history><permissions><copyright-statement>&#169; Copyright  2014 by authors and Scientific Research Publishing Inc. </copyright-statement><copyright-year>2014</copyright-year><license><license-p>This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/</license-p></license></permissions><abstract><p><html>
 <head></head>
 
  Polygonal numbers and sums of squares of primes are distinct fields of number theory. Here we consider sums of squares of consecutive (of order and rank) polygonal numbers. We try to express sums of squares of polygonal numbers of consecutive orders in matrix form. We also try to find the solution of a Diophantine equation 
  <img src="Edit_dfab9f0a-be14-44a6-abcb-d49a46d2119f.bmp" alt="" />
  in terms of polygonal numbers.
 
</html></p></abstract><kwd-group><kwd>Polygonal Numbers</kwd><kwd> Sums of Squares</kwd><kwd> Triangular Numbers</kwd></kwd-group></article-meta></front><body><sec id="s1"><title>1. Introduction [<xref ref-type="bibr" rid="scirp.65099-ref1">1</xref>]</title><p>Polygonal numbers have been meticulously studied since their very beginnings in ancient Greece. Numerous discoveries stemmed from these peculiar numbers can be seen in the basic fundamental group work of number theory today with finding such as pascal’s triangle and Fermat triangular number theorem. It becomes a popular field of research for mathematicians. The concept of polygonal numbers was first defined by the Greek Mathematical hypsicles in the year 170 BC. If the polygonal numbers are divided successively into triangles it will ultimately end up with right triangle. The right triangles immediately remind us of Pythagorean property. This leads to the idea of finding sums of squares of consecutive polygonal numbers. In this paper we calculate sums of squares polygonal numbers of consecutive orders. We also calculate the sums of squares of m-gonal numbers of consecutive ranks. We analyze some properties of the above.</p></sec><sec id="s2"><title>2. Polygonal Number</title><sec id="s2_1"><title>2.1. Definition</title><p>For <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x7.png" xlink:type="simple"/></inline-formula></p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x8.png" xlink:type="simple"/></inline-formula>with <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x9.png" xlink:type="simple"/></inline-formula></p><p>are called generalized m-gonal numbers.</p><p>Also <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x10.png" xlink:type="simple"/></inline-formula></p><p>where</p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x11.png" xlink:type="simple"/></inline-formula>with<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x12.png" xlink:type="simple"/></inline-formula>, a triangular number of rank <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x13.png" xlink:type="simple"/></inline-formula></p><p>Sums of Squares of Polygonal numbers of Consecutive Orders of Same Rank</p></sec><sec id="s2_2"><title>2.2. Proposition</title><disp-formula id="scirp.65099-formula92"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x14.png"  xlink:type="simple"/></disp-formula><p>Proof</p><disp-formula id="scirp.65099-formula93"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x15.png"  xlink:type="simple"/></disp-formula><p>Sums of squares of Polygonal numbers of Consecutive Orders in Matrix Form [<xref ref-type="bibr" rid="scirp.65099-ref2">2</xref>]</p><p>Expressing the coefficients of <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x16.png" xlink:type="simple"/></inline-formula> and <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x17.png" xlink:type="simple"/></inline-formula> for 3 consecutive sums of squares in a <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x18.png" xlink:type="simple"/></inline-formula> matrix the coefficients of sums of squares of any three consecutive terms of higher order can be obtained.</p><p>The coefficient matrix <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x19.png" xlink:type="simple"/></inline-formula> of sums of squares polygonal numbers is</p><disp-formula id="scirp.65099-formula94"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x20.png"  xlink:type="simple"/></disp-formula><p>for<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x21.png" xlink:type="simple"/></inline-formula>.</p><p>In general,</p><disp-formula id="scirp.65099-formula95"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x22.png"  xlink:type="simple"/></disp-formula><p>where <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x23.png" xlink:type="simple"/></inline-formula></p><p>Recursive matrix form</p><p>Consider the initial matrix as the coefficients of<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x24.png" xlink:type="simple"/></inline-formula>, and <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x24.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x25.png" xlink:type="simple"/></inline-formula> in <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x24.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x25.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x26.png" xlink:type="simple"/></inline-formula> for <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x24.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x25.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x26.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x27.png" xlink:type="simple"/></inline-formula></p><disp-formula id="scirp.65099-formula96"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x28.png"  xlink:type="simple"/></disp-formula><p>The elements of next order <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x29.png" xlink:type="simple"/></inline-formula> depends on the previous order elements in <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x29.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x30.png" xlink:type="simple"/></inline-formula> except the elements of first row.</p><disp-formula id="scirp.65099-formula97"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x31.png"  xlink:type="simple"/></disp-formula><p>The first two rows elements of <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x32.png" xlink:type="simple"/></inline-formula> are already occurred in <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x32.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x33.png" xlink:type="simple"/></inline-formula> and the third row elements are depend on the elements of first two row elements.</p><disp-formula id="scirp.65099-formula98"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x34.png"  xlink:type="simple"/></disp-formula><p>In general, the matrix of order <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x35.png" xlink:type="simple"/></inline-formula> depends on the previous order matrix elements<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x35.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x36.png" xlink:type="simple"/></inline-formula>.</p><disp-formula id="scirp.65099-formula99"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x37.png"  xlink:type="simple"/></disp-formula><p>Sums of squares of Polygonal Numbers with Consecutive ranks n, n+1.</p></sec><sec id="s2_3"><title>2.3. Proposition [<xref ref-type="bibr" rid="scirp.65099-ref3">3</xref>]</title><disp-formula id="scirp.65099-formula100"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x38.png"  xlink:type="simple"/></disp-formula><p>Proof</p><disp-formula id="scirp.65099-formula101"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x39.png"  xlink:type="simple"/></disp-formula><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x40.png" xlink:type="simple"/></inline-formula>.</p></sec><sec id="s2_4"><title>2.4. Proposition</title><p>The Triple <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x41.png" xlink:type="simple"/></inline-formula> form the solution of the Diophantine equation <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x41.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x42.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x41.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x42.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x43.png" xlink:type="simple"/></inline-formula>is a constant.</p><p>Proof</p><p>Consider the Diophantine equation <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x44.png" xlink:type="simple"/></inline-formula></p><p>We try for the solution in polygonal numbers.</p><p>Take <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x45.png" xlink:type="simple"/></inline-formula></p><disp-formula id="scirp.65099-formula102"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x46.png"  xlink:type="simple"/></disp-formula><disp-formula id="scirp.65099-formula103"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x47.png"  xlink:type="simple"/></disp-formula><p>Taking <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x48.png" xlink:type="simple"/></inline-formula> it is clear that the triple <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x48.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x49.png" xlink:type="simple"/></inline-formula> form the solution of the given equation in the order<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x48.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x49.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x50.png" xlink:type="simple"/></inline-formula>.</p></sec><sec id="s2_5"><title>2.5. Proposition</title><disp-formula id="scirp.65099-formula104"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x51.png"  xlink:type="simple"/></disp-formula><p>Proof</p><disp-formula id="scirp.65099-formula105"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x52.png"  xlink:type="simple"/></disp-formula><disp-formula id="scirp.65099-formula106"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x53.png"  xlink:type="simple"/></disp-formula></sec><sec id="s2_6"><title>2.6. Proposition</title><disp-formula id="scirp.65099-formula107"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x54.png"  xlink:type="simple"/></disp-formula><p>Proof</p><disp-formula id="scirp.65099-formula108"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x55.png"  xlink:type="simple"/></disp-formula><disp-formula id="scirp.65099-formula109"><graphic  xlink:href="http://html.scirp.org/file/4-5301069x56.png"  xlink:type="simple"/></disp-formula></sec></sec><sec id="s3"><title>3. Conclusion</title><p>It is observed that the polygonal numbers of consecutive ranks constitute the solution of the Diophantine equation <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x57.png" xlink:type="simple"/></inline-formula> in the order<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x57.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x58.png" xlink:type="simple"/></inline-formula>. Also we try to find that sums of squares of polygonal numbers are general.</p></sec><sec id="s4"><title>Cite this paper</title><p>A. Gnanam,B. Anitha, (2016) Sums of Squares of Polygonal Numbers. Advances in Pure Mathematics,06,297-301. doi: 10.4236/apm.2016.64019</p></sec><sec id="s5"><title>Notations</title><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x59.png" xlink:type="simple"/></inline-formula>: Polygonal number of order m rank n.</p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-5301069x60.png" xlink:type="simple"/></inline-formula>: Triangular Number.</p><p>16MAG<sub>n</sub>: Magna Number order n.</p></sec></body><back><ref-list><title>References</title><ref id="scirp.65099-ref1"><label>1</label><mixed-citation publication-type="other" xlink:type="simple">Sun, Z.-W. (2009) On Universal Sums of Polygonal Numbers. arxiv: 0905.0635.</mixed-citation></ref><ref id="scirp.65099-ref2"><label>2</label><mixed-citation publication-type="other" xlink:type="simple">Kwak, J.H. and Hong, S. (2004) Linear Algebra. 2nd Edition, Birkhauser, xvi+390 pp.</mixed-citation></ref><ref id="scirp.65099-ref3"><label>3</label><mixed-citation publication-type="other" xlink:type="simple">Gopalan, M.A. and Gnanam, A. (2009) Magna Numbers. Indian Journal of Mathematical Sciences, 5, 33-34.</mixed-citation></ref></ref-list></back></article>