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 A088728 #4 Oct 01 2013 17:57:45 %S A088728 158,239,292,502,542,631,1203,1381,2189,2461,2797,2949,3190,3494,3537, %T A088728 4849,4883,5053,6140,6619,6730,6761,7557,7604,8912,8961,9018,9043, %U A088728 9109,9253,9289,9316,9733,10142,10409,10652,11515,12231,12234,12653,13472 %N A088728 p such that p^4 + q^4 = r^4 + s^4 = a(n). %H A088728 D. J. Bernstein, <a href="http://cr.yp.to/sortedsums/two4.1000000">List of 516 primitive solutions p^4 + q^4 = r^4 + s^4</a> %Y A088728 Cf. A003824, A088665. %K A088728 fini,nonn %O A088728 1,1 %A A088728 _Cino Hilliard_, Nov 22 2003