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 A074688 #6 Oct 15 2015 10:55:23 %S A074688 0,1,3,2,7,8,4,5,6,18,20,21,22,17,10,9,11,12,13,14,15,19,16,50,55,61, %T A074688 57,49,62,59,63,64,58,46,45,54,48,26,27,23,24,25,29,28,30,31,32,33,34, %U A074688 35,36,38,37,39,40,41,51,52,56,60,42,43,44,47,53,148,162,167,181,147 %N A074688 Permutation of natural numbers induced by the Catalan bijection gmA074688! acting on the parenthesizations encoded by A014486/A063171. %H A074688 A. Karttunen, <a href="http://www.iki.fi/~kartturi/matikka/Nekomorphisms/gatomorf.htm">Gatomorphisms</a> (with the complete Scheme source) %H A074688 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %o A074688 (Scheme function implementing this automorphism on list-structures:) %o A074688 (define (gmA074688! s) (cond ((pair? s) (gmA074688! (cdr s)) (gmrobr! s) (gmA074688! (car s)))) s) %Y A074688 Inverse of A074687 and also a(n) = A057163(A074687(A057163(n))). Cf. A074681-A074690. Occurs in A073200. %K A074688 nonn %O A074688 0,3 %A A074688 _Antti Karttunen_, Sep 11 2002