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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.

A268712 Permutation of natural numbers: a(1) = 1, a(2n) = A268677(a(n)), a(2n+1) = A268678(1+a(n)).

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%I A268712 #6 Feb 13 2016 23:17:58
%S A268712 1,2,3,6,4,9,5,13,11,10,7,21,18,12,8,29,23,25,20,24,19,14,15,45,40,39,
%T A268712 34,28,22,17,16,62,56,49,42,54,48,44,37,51,47,43,36,30,26,33,27,95,87,
%U A268712 84,75,80,74,73,65,61,53,46,41,38,32,35,31,129,120,115,108,100,93,88,82,112,105,99,92,94,86,78,70
%N A268712 Permutation of natural numbers: a(1) = 1, a(2n) = A268677(a(n)), a(2n+1) = A268678(1+a(n)).
%C A268712 This sequence can be represented as a binary tree. Each left hand child is produced as A268677(n), and each right hand child as A268678(1+n), when the parent node contains n:
%C A268712                                      |
%C A268712                   ...................1...................
%C A268712                  2                                       3
%C A268712        6......../ \........4                   9......../ \........5
%C A268712       / \                 / \                 / \                 / \
%C A268712      /   \               /   \               /   \               /   \
%C A268712     /     \             /     \             /     \             /     \
%C A268712   13       11         10       7          21       18         12       8
%C A268712 29 23    25  20     24  19   14 15      45  40   39  34     28  22   17 16
%C A268712 etc.
%H A268712 Antti Karttunen, <a href="/A268712/b268712.txt">Table of n, a(n) for n = 1..16383</a>
%H A268712 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%F A268712 a(1) = 1, after which: a(2n) = A268677(a(n)), a(2n+1) = A268678(1+a(n)).
%o A268712 (Scheme, with memoization-macro definec)
%o A268712 (definec (A268712 n) (cond ((= 1 n) n) ((even? n) (A268677 (A268712 (/ n 2)))) (else (A268678 (+ 1 (A268712 (/ (- n 1) 2)))))))
%Y A268712 Inverse: A268711.
%Y A268712 Cf. A268677, A268678.
%K A268712 nonn,tabf
%O A268712 1,2
%A A268712 _Antti Karttunen_, Feb 11 2016