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 A270426 #14 Mar 25 2016 23:01:52 %S A270426 1,2,3,4,7,6,5,8,9,14,19,12,13,10,21,16,25,18,11,28,63,38,23,24,17,26, %T A270426 27,20,15,42,37,32,57,50,73,36,31,22,39,56,33,126,91,76,117,46,61,48, %U A270426 43,34,75,52,79,54,29,40,67,30,49,84,157,74,45,64,147,114,41,100,183,146,77,72,35,62,51,44,55,78,53,112,193,66 %N A270426 Permutation of natural numbers: a(1) = 1, a(2n) = 2*a(n), a(2n+1) = A265341(a(n)). %C A270426 This sequence can be represented as a binary tree. Each left hand child will contain 2n, and each right hand child will contain A265341(n), when the parent node contains n: %C A270426 1 %C A270426 ................../ \.................. %C A270426 2 3 %C A270426 4......../ \........7 6......../ \........5 %C A270426 / \ / \ / \ / \ %C A270426 / \ / \ / \ / \ %C A270426 / \ / \ / \ / \ %C A270426 8 9 14 19 12 13 10 21 %C A270426 16 25 18 11 28 63 38 23 24 17 26 27 20 15 42 37 %C A270426 etc. %H A270426 Antti Karttunen, <a href="/A270426/b270426.txt">Table of n, a(n) for n = 1..8192</a> %H A270426 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A270426 a(1) = 1, a(2n) = 2*a(n), a(2n+1) = A265341(a(n)). %o A270426 (Scheme, with memoization-macro definec) %o A270426 (definec (A270426 n) (cond ((= 1 n) n) ((even? n) (* 2 (A270426 (/ n 2)))) (else (A265341 (A270426 (/ (- n 1) 2)))))) %Y A270426 Inverse: A270425. %Y A270426 Cf. A265341. %K A270426 nonn,base,less,tabf %O A270426 1,2 %A A270426 _Antti Karttunen_, Mar 17 2016