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 A130925 #5 Mar 31 2012 13:21:16 %S A130925 0,1,3,2,6,8,7,4,5,14,15,19,21,22,16,17,20,9,10,18,11,12,13,37,38,39, %T A130925 40,41,51,52,56,62,59,60,64,63,58,42,43,44,45,46,53,54,55,23,24,61,25, %U A130925 26,27,47,48,57,28,29,49,30,31,32,50,33,34,35,36,107,108,109,110,111 %N A130925 Signature permutation of a Catalan automorphism: Inverse FORK-transform of automorphism *A120706. %C A130925 This is the unique Catalan automorphism f, such that *A120706 = (FORK f). See A122201 for the definition of FORK. %H A130925 A. Karttunen, <a href="/A130925/b130925.txt">Table of n, a(n) for n = 0..2055</a> %H A130925 <a href="/index/Per#IntegerPermutationCatAuto">Index entries for signature-permutations of Catalan automorphisms</a> %o A130925 (Destructive Scheme implementation of this automorphism, which acts on S-expressions, i.e. list-structures:) %o A130925 (define (*A130925! s) (cond ((pair? s) (*A074679! s) (cond ((pair? (car s)) (*A120706! (caar s)) (*A120705! (cdar s)) (*A120705! (car s)))))) s) %Y A130925 Inverse: A130926. Cf. A130923 & A130924. %K A130925 nonn %O A130925 0,3 %A A130925 _Antti Karttunen_, Jun 11 2007