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 A269858 #5 Mar 07 2016 12:32:30 %S A269858 1,2,3,4,5,6,11,8,7,9,31,10,127,18,13,14,709,12,5381,15,19,45,52711, %T A269858 16,17,165,23,27,648391,21,9737333,22,29,856,41,20,174440041,6185,61, %U A269858 24,3657500101,28,88362852307,63,43,58644,2428095424619,25,59,26,37,212,75063692618249,34,67,39,47 %N A269858 Permutation of natural numbers: a(1) = 1, a(2n) = A065090(1+a(n)), a(2n+1) = A000040(a(A268674(2n+1))). %C A269858 Terms for prime positions copied from A007097. %H A269858 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A269858 a(1) = 1, a(2) = 2, for n > 2, if n is even, a(n) = A002808(a(n/2)-1), and for odd n, a(n) = A000040(a(A268674(n))). %F A269858 As a composition of other permutations: %F A269858 a(n) = A237739(A252756(n)). %F A269858 Other identities. For all n >= 1: %F A269858 a(A000040(n)) = A007097(n). [Maps primes to the primeth recurrence.] %o A269858 (Scheme, with memoization-macro definec) %o A269858 (definec (A269858 n) (cond ((<= n 1) n) ((even? n) (A065090 (+ 1 (A269858 (/ n 2))))) (else (A000040 (A269858 (A268674 n)))))) %Y A269858 Inverse: A269857. %Y A269858 Cf. A000040, A007097, A065090, A268674. %Y A269858 Related or similar permutations: A237739, A252756, A269848. %K A269858 nonn %O A269858 1,2 %A A269858 _Antti Karttunen_, Mar 06 2016