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 A129609 #6 Mar 31 2012 13:21:14 %S A129609 0,1,3,2,7,6,8,4,5,17,18,14,15,16,20,19,21,9,10,22,11,12,13,45,46,48, %T A129609 49,50,37,38,39,40,41,42,43,44,47,54,55,51,52,53,57,56,58,23,24,59,25, %U A129609 26,27,61,60,62,28,29,63,30,31,32,64,33,34,35,36,129,130,132,133,134 %N A129609 Signature-permutation of a Catalan automorphism, row 65167 of A089840. %C A129609 Automorphism *A074679 = ENIPS(*A129609). See the definition given in A122204. %H A129609 A. Karttunen, <a href="/A129609/b129609.txt">Table of n, a(n) for n = 0..2055</a> %H A129609 A. Karttunen, <a href="/A089840/a089840p.txt">Prolog-program which illustrates the construction of this and similar nonrecursive Catalan automorphisms.</a> %H A129609 <a href="/index/Per#IntegerPermutationCatAuto">Index entries for signature-permutations of Catalan automorphisms</a> %o A129609 (Constructive and destructive Scheme implementation of this automorphism. These act on S-expressions, i.e. list-structures:) %o A129609 (define (*A129609 s) (cond ((pair? s) (*A074679 (cons (car s) (*A074680 (cdr s))))) (else s))) %o A129609 (define (*A129609! s) (cond ((pair? s) (*A074680! (cdr s)) (*A074679! s))) s) %Y A129609 Inverse: A129610. %K A129609 nonn %O A129609 0,3 %A A129609 _Antti Karttunen_, May 22 2007