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 A131142 #5 Mar 31 2012 13:21:17 %S A131142 0,1,2,3,5,4,6,7,8,13,12,11,10,9,15,14,16,17,18,19,20,21,22,36,35,34, %T A131142 31,32,33,30,29,27,26,28,25,24,23,41,40,39,38,37,43,42,44,45,46,47,48, %U A131142 49,50,52,51,53,54,55,56,57,58,59,60,61,62,63,64,106,105,104,100,101 %N A131142 Signature permutation of a Catalan automorphism: row 3 of A122286. %C A131142 Derived from automorphism *A130342 with recursion scheme SPINE. %H A131142 A. Karttunen, <a href="/A131142/b131142.txt">Table of n, a(n) for n = 0..2055</a> %H A131142 <a href="/index/Per#IntegerPermutationCatAuto">Index entries for signature-permutations of Catalan automorphisms</a> %Y A131142 Inverse: A131141. %K A131142 nonn %O A131142 0,3 %A A131142 _Antti Karttunen_, Jun 20 2007