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 A269866 #7 Mar 15 2016 00:16:35 %S A269866 1,2,3,4,5,6,9,8,7,10,13,12,21,18,11,16,25,14,33,20,19,26,29,24,17,42, %T A269866 15,36,53,22,73,32,27,50,37,28,45,66,43,40,57,38,81,52,23,58,77,48,49, %U A269866 34,51,84,117,30,41,72,67,106,169,44,213,146,39,64,85,54,89,100,59,74,109,56,149,90,35,132,101,86,113,80,31 %N A269866 Permutation of natural numbers: a(1) = 1, a(2n) = 2*a(n), a(2n+1) = 1 + 2*a(A268674(2n+1)-1). %H A269866 Antti Karttunen, <a href="/A269866/b269866.txt">Table of n, a(n) for n = 1..8192</a> %H A269866 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A269866 a(1) = 1, a(2n) = 2*a(n), a(2n+1) = 1 + 2*a(A268674(2n+1)-1). %o A269866 (Scheme, with memoization-macro definec) %o A269866 (definec (A269866 n) (cond ((<= n 1) n) ((even? n) (* 2 (A269866 (/ n 2)))) (else (+ 1 (* 2 (A269866 (- (A268674 n) 1))))))) %Y A269866 Inverse: A269865. %Y A269866 Cf. A268674. %Y A269866 Related or similar permutations: A269867, A249813, A252756, A270196. %Y A269866 Differs from similarly constructed A246376 for the first time at n=21, where a(21) = 19, instead of 15. %K A269866 nonn %O A269866 1,2 %A A269866 _Antti Karttunen_, Mar 12 2016