This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A223857 #23 Apr 03 2013 11:49:23 %S A223857 720,23400,81600,235200,852600,1305360,1328400,5314320,8414280, %T A223857 9434880,16893240,18498480,33918720,43995600,45561600,46652760, %U A223857 57757440,106226640,108617760,154736400,155263680,184041000,235227600,361712400,417740400,451760400,471711240 %N A223857 Ordered products of the perimeter and the sides of primitive Pythagorean triangles. %C A223857 Considering the set of primitive Pythagorean triangles with sides (A, B, C), the sequence gives the values (A+B+C)*(A*B*C), in increasing order. %C A223857 It is a challenge to find a pair of primitive Pythagorean triangles such that product of perimeter and the sides is equal. %H A223857 Wikipedia, <a href="http://en.wikipedia.org/wiki/Pythagorean_triple">Pythagorean Triples</a> %e A223857 a(1) = (3+4+5)*(3*4*5) = 720. %e A223857 a(2) = (5+12+13)*(5*12*13) = 23400. %Y A223857 Cf. A063011, A024364. %K A223857 nonn,easy %O A223857 1,1 %A A223857 _Mihir Mathur_, Apr 02 2013 %E A223857 Corrected and extended by _Giovanni Resta_, Apr 03 2013