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 A269171 #16 Mar 03 2016 22:48:23 %S A269171 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,23,20,21,22,25,24,19,26, %T A269171 27,28,29,30,37,32,33,34,35,36,41,46,39,40,43,42,47,44,45,50,53,48,31, %U A269171 38,51,52,61,54,49,56,57,58,67,60,71,74,63,64,65,66,77,68,69,70,83,72,89,82,75,92,59,78,91,80,81,86,97,84,79,94,87,88,107,90,85,100 %N A269171 Permutation of natural numbers: a(1) = 1, a(2n) = 2*a(n), a(2n+1) = A269379(a(A268674(2n+1))). %H A269171 Antti Karttunen, <a href="/A269171/b269171.txt">Table of n, a(n) for n = 1..8192</a> %H A269171 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A269171 a(1) = 1, then after for even n, a(n) = 2*a(n/2), and for odd n, a(n) = A269379(a(A268674(n))). %F A269171 a(1) = 1, for n > 1, a(n) = A255127(A055396(n), a(A078898(n))). %F A269171 As a composition of other permutations: %F A269171 a(n) = A269385(A252756(n)). %F A269171 a(n) = A269387(A252754(n)). %F A269171 Other identities. For all n >= 1: %F A269171 A000035(a(n)) = A000035(n). [Preserves the parity of n.] %F A269171 a(A008578(n)) = A003309(n). [Maps noncomposites to Ludic numbers.] %o A269171 (Scheme, two versions, both using memoization-macro definec) %o A269171 (definec (A269171 n) (cond ((<= n 1) n) ((even? n) (* 2 (A269171 (/ n 2)))) (else (A269379 (A269171 (A268674 n)))))) %o A269171 (definec (A269171 n) (if (<= n 1) n (A255127bi (A055396 n) (A269171 (A078898 n))))) ;; Code for A255127bi given in A255127. %Y A269171 Inverse: A269172. %Y A269171 Cf. A000035, A003309, A008578, A055396, A078898, A268674, A255127, A269379. %Y A269171 Related or similar permutations: A260741, A260742, A269355, A269357, A255421, A252754, A252756, A269385, A269387. %Y A269171 Cf. also A269393 (a(3n)/3) and A269395. %Y A269171 Differs from A255407 for the first time at n=38, where a(38) = 46, while A255407(38) = 38. %K A269171 nonn %O A269171 1,2 %A A269171 _Antti Karttunen_, Mar 03 2016