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 A228914 #15 Dec 30 2015 15:03:02
%S A228914 4,5,9,12,15,20,21,22,24,26,29,30,31,32,34,35,36,37,38,40,43,44,53,55,
%T A228914 56,58,59,60,62,64,66,67,68,69,70,71,74,76,77,80,82,84,86,87,88,90,91,
%U A228914 92,94,95,102,103,104,105,106,108,109,110,112,113,115,117,122,123,129,131,132,133,135,136,137,138,139,140,141,143,144,147
%N A228914 Positive integers N such that 1/N = p/q - q/p + r/s - s/r for some positive integers p,q,r,s.
%C A228914 Positive integer N belongs to this sequence if and only if the elliptic curve y^2 = x^3 + (8*N^2+1)*x^2 + 16*N^4*x has positive rank.
%o A228914 (PARI) { isA228914(n) = ellanalyticrank(ellinit([0, 8*n^2+1, 0, 16*n^4, 0]))[1]; } /* _Max Alekseyev_, Dec 30 2015 */
%Y A228914 Cf. A206334, A228380
%K A228914 nonn
%O A228914 1,1
%A A228914 _Thomas Bokk_, Sep 13 2013
%E A228914 More terms from _Max Alekseyev_, Sep 13 2013