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 A117337 #4 Mar 30 2012 18:36:56 %S A117337 0,0,1,-4,24,-157,1176,-9853,91498,-933451,10386908,-125292129, %T A117337 1629597910,-22746009423,339288465552,-5388025686685,90782990910394, %U A117337 -1617895300046011,30412104692215604,-601422325704360009,12483373271662252222,-271375594220745999111 %N A117337 Column 2 of triangle A117335. %Y A117337 Cf. A117335 (triangle), A117336 (column 1), A117338 (row sums). %K A117337 sign %O A117337 0,4 %A A117337 _Paul D. Hanna_, Mar 09 2006