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 A329906 #15 Jan 13 2020 20:39:34 %S A329906 1,2,3,4,5,11,6,9,7,23,15,38,8,20,13,22,10,44,30,110,19,69,49,128,12, %T A329906 41,27,72,17,43,29,54,14,79,56,272,37,181,136,482,26,118,86,307,61, %U A329906 208,156,424,16,73,52,190,34,123,89,242,24,77,55,147,36,93,66,114,18,131,97,596,68,416,323,1448,48,286,218,990,164,711 %N A329906 a(0) = 1; a(1) = 2; after which a(2n) = A329898(a(n)), a(2n+1) = A330683(a(n)). %C A329906 Note the indexing: domain begins from zero, but the range does not include it. %H A329906 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A329906 a(0) = 1; a(1) = 2; after which a(2n) = A329898(a(n)), a(2n+1) = A330683(a(n)). %F A329906 a(n) = A329901(A163511(n)). %e A329906 This irregular table can be represented as a binary tree. Each child to the left is obtained by applying A329898 the parent, and each child to the right is obtained by applying A330683 to the parent: %e A329906 1 %e A329906 | %e A329906 ...................2................... %e A329906 3 4 %e A329906 5......../ \........11 6......../ \........9 %e A329906 / \ / \ / \ / \ %e A329906 / \ / \ / \ / \ %e A329906 / \ / \ / \ / \ %e A329906 7 23 15 38 8 20 13 22 %e A329906 10 44 30 110 19 69 49 128 12 41 27 72 17 43 29 54 %e A329906 etc. %o A329906 (PARI) A329906(n) = if(n<2,1+n,if(!(n%2),A329898(A329906(n/2)),A330683(A329906(n\2)))); %Y A329906 Cf. A329905 (inverse permutation). %Y A329906 Cf. A163511, A181815, A329897, A329898, A329901, A330683. %K A329906 nonn %O A329906 0,2 %A A329906 _Antti Karttunen_, Dec 24 2019