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 A129607 #6 Mar 31 2012 13:21:14 %S A129607 0,1,2,3,4,6,5,7,8,9,10,11,16,19,14,15,12,17,18,13,20,21,22,23,24,25, %T A129607 26,27,28,29,30,44,47,33,53,56,60,37,38,39,43,52,42,40,31,45,46,32,48, %U A129607 49,50,51,41,34,54,55,35,57,58,59,36,61,62,63,64,65,66,67,68,69,70,71 %N A129607 Signature-permutation of a Catalan automorphism: swap the left and right subtree of degree 2 general trees. %C A129607 Otherwise like automorphism *A072796, except that this involution exchanges the two leftmost subtrees of a general tree ONLY when the degree of the tree is two. Automorphism *A129608 = SPINE(*A129607) = ENIPS(*A129607). See the definitions given in A122203 and A122204. %H A129607 A. Karttunen, <a href="/A129607/b129607.txt">Table of n, a(n) for n = 0..2055</a> %H A129607 A. Karttunen, <a href="/A089840/a089840p.txt">Prolog-program which illustrates the construction of this and similar nonrecursive Catalan automorphisms.</a> %H A129607 <a href="/index/Per#IntegerPermutationCatAuto">Index entries for signature-permutations of Catalan automorphisms</a> %o A129607 (Constructive and destructive Scheme implementation of this automorphism. These act on S-expressions, i.e. list-structures:) %o A129607 (define (*A129607 s) (if (= 2 (length s)) (*A072796 s) s)) %o A129607 (define (*A129607! s) (if (= 2 (length s)) (*A072796! s)) s) %Y A129607 Row 3608 of A089840. %K A129607 nonn %O A129607 0,3 %A A129607 _Antti Karttunen_, May 22 2007