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 A154352 #4 Mar 30 2012 18:51:59 %S A154352 0,1,1,0,-1,-1,0,-21,-21,0,21,21,0,-903,-903,0,903,903,0,-38829, %T A154352 -38829,0,38829,38829,0,-1669647,-1669647,0,1669647,1669647,0, %U A154352 -71794821,-71794821,0,71794821,71794821,0,-3087177303,-3087177303,0,3087177303,3087177303,0 %N A154352 a(n)=A132658(n+1)-2*A132658(n). %K A154352 sign %O A154352 0,8 %A A154352 _Paul Curtz_, Jan 07 2009 %E A154352 Edited and extended by _R. J. Mathar_, Feb 27 2009