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 A131000 #5 Mar 31 2012 13:21:16 %S A131000 0,1,3,2,7,8,6,4,5,18,17,20,22,21,16,19,14,9,10,15,11,12,13,50,49,48, %T A131000 46,45,55,54,61,64,63,57,62,59,58,47,44,53,60,56,42,51,37,23,24,38,25, %U A131000 26,27,43,52,39,28,29,40,30,32,31,41,33,34,36,35,147,148,146,142,143 %N A131000 Signature permutation of a Catalan automorphism: row 21 of A122287. %C A131000 Derived from automorphism *A130360 with recursion scheme FORK. %H A131000 A. Karttunen, <a href="/A131000/b131000.txt">Table of n, a(n) for n = 0..2055</a> %H A131000 <a href="/index/Per#IntegerPermutationCatAuto">Index entries for signature-permutations of Catalan automorphisms</a> %Y A131000 Inverse: A130999. %K A131000 nonn %O A131000 0,3 %A A131000 _Antti Karttunen_, Jun 20 2007