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 A074685 #6 Oct 15 2015 10:55:23 %S A074685 0,1,3,2,6,7,8,5,4,15,14,16,17,18,19,20,21,11,12,22,13,10,9,39,40,41, %T A074685 38,37,43,42,44,45,46,47,48,49,50,52,51,53,54,55,56,57,58,29,28,59,30, %U A074685 31,32,60,61,62,33,34,63,35,25,26,64,36,27,24,23,113,112,114,115,116 %N A074685 Permutation of natural numbers induced by the Catalan bijection gmA074685! acting on the parenthesizations encoded by A014486/A063171. %H A074685 A. Karttunen, <a href="http://www.iki.fi/~kartturi/matikka/Nekomorphisms/gatomorf.htm">Gatomorphisms</a> (with the complete Scheme source) %H A074685 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %o A074685 (Scheme function implementing this automorphism on list-structures:) %o A074685 (define (gmA074685! s) (cond ((pair? s) (gmrobl! s) (gmA074685! (cdr s)))) s) %Y A074685 Inverse of A074686. a(n) = A057163(A074689(A057163(n))). Occurs in A073200 as row 5572436. %K A074685 nonn %O A074685 0,3 %A A074685 _Antti Karttunen_, Sep 11 2002