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 A256541 #4 Apr 02 2015 17:04:35 %S A256541 1,2,-1,5,-1,-1,-1,7,-1,-1,-1,7,-1,-1,-1,8,-1,-1,-1,-1,7,-1,-1,47,-41, %T A256541 -1,-1,-1,14,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,11,1,1,1,1,1,1,1,1,1,1,1,1, %U A256541 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,133,-121,-1,-1 %N A256541 First differences of A166133. %C A256541 a(n) != 0; abs(a(A256543(n))) = 1. %H A256541 Reinhard Zumkeller, <a href="/A256541/b256541.txt">Table of n, a(n) for n = 1..10000</a> %o A256541 (Haskell) %o A256541 a256541 n = a256541_list !! (n-1) %o A256541 a256541_list = zipWith (-) (tail a166133_list) a166133_list %Y A256541 Cf. A166133, A256543. %K A256541 sign %O A256541 1,2 %A A256541 _Reinhard Zumkeller_, Apr 01 2015