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 A089870 #8 Oct 15 2015 10:55:25 %S A089870 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,22,21,23,24,25, %T A089870 26,27,28,29,30,31,32,33,34,36,35,37,38,39,40,41,42,43,44,45,46,47,48, %U A089870 50,49,51,52,53,54,55,60,61,63,62,56,57,64,59,58,65,66,67,68,69 %N A089870 Permutation of natural numbers induced by the Catalan bijection gma089870 acting on the parenthesizations/binary trees encoded by A014486/A063171. %C A089870 This Catalan bijection arises when we apply the Catalan bijection A085170 to each top-level subtree (sub-parenthesization). %H A089870 A. Karttunen, <a href="/A089408/a089408.c.txt">C-program for computing this sequence</a> %H A089870 <a href="/index/Per#IntegerPermutationCatAuto">Index entries for signature-permutations induced by Catalan automorphisms</a> %o A089870 (Scheme function implementing this automorphism on list-structures:) %o A089870 (define (gma089870! s) (for-each gma085170! s) s) %Y A089870 Inverse of A089869. %Y A089870 Number of cycles: A090827. Number of fixed-points: A000129. Max. cycle size: A086586. LCM of cycle sizes: A086587. (In range [A014137(n-1)..A014138(n-1)] of this permutation, possibly shifted one term left or right). %K A089870 nonn %O A089870 0,3 %A A089870 _Antti Karttunen_, Dec 20 2003