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 A123718 #6 Mar 31 2012 13:21:12 %S A123718 0,1,2,3,4,6,5,8,7,9,14,10,19,16,11,15,12,21,22,13,20,17,18,23,37,24, %T A123718 51,42,25,38,26,56,60,27,53,44,47,28,39,29,52,43,30,40,31,58,59,32,62, %U A123718 63,64,33,41,34,57,61,35,54,45,46,36,55,48,49,50,65,107,66,149,121,67 %N A123718 Signature permutation of a Catalan automorphism: row 253 of table A122204. %C A123718 This is the signature-permutation of Catalan automorphism which is derived from nonrecursive Catalan automorphism *A123503 with the recursion schema ENIPS (defined in A122204). See the comments at A123717. %H A123718 <a href="/index/Per#IntegerPermutationCatAuto">Index entries for signature-permutations of Catalan automorphisms</a> %o A123718 (Scheme function, destructive implementation of this automorphism acting on S-expressions:) (define *A123718! (!ENIPS *A123503!)) %Y A123718 Inverse: A123717. a(n) = A089854(A057510(n)). Row 253 of A122204. %K A123718 nonn %O A123718 0,3 %A A123718 _Antti Karttunen_, Oct 11 2006