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 A203509 #7 Feb 28 2014 09:18:38 %S A203509 1,2,4,548,9420,3852,34864,19084,15296,154560176,7180221844,887102780, %T A203509 211332046788,71893259484,20454788424,5986072942766808, %U A203509 5988933869570752,22285488224,2756032824242080,17677170921656,679436626785756,20936052371230100988 %N A203509 Row sums of triangle A178473. %C A203509 Conjecture. If prime p==1 (mod 4), then a((p-1)/4)==2 (mod p); if prime p==3 (mod 4), then a((p-1)/2)==2 (mod p). %Y A203509 Cf. A202941, A202917, A203269, A203278, A203484, A178473, A203498. %K A203509 nonn %O A203509 0,2 %A A203509 _Vladimir Shevelev_ and _Peter J. C. Moses_, Jan 02 2012