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 A270201 #7 Mar 25 2016 07:47:54 %S A270201 1,2,4,8,16,32,64,128,3,256,5,6,512,10,9,17,12,33,1024,20,65,18,129, %T A270201 34,24,66,2048,40,130,36,258,257,68,48,132,7,513,4096,11,13,80,260,72, %U A270201 516,514,1025,21,136,96,264,19,14,1026,35,25,67,8192,2049,22,26,160,520,144,1032,1028,2050,41,42,272,192,131,528,37,259,38,69,28 %N A270201 Permutation of natural numbers: a(1) = 1, a(A270189(1+n)) = 2 * a(n), a(A270190(n)) = 1 + 2*a(n). %H A270201 Antti Karttunen, <a href="/A270201/b270201.txt">Table of n, a(n) for n = 1..10001</a> %H A270201 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A270201 a(1) = 1, for n > 1, if A137264(n) = 0 [when n is in A270190], a(n) = 1 + 2*a(A269850(n)), otherwise a(n) = 2 * a(A269849(n)-1). %o A270201 (Scheme, with memoization-macro definec) %o A270201 (definec (A270201 n) (cond ((= 1 n) n) ((not (zero? (A137264 n))) (* 2 (A270201 (+ -1 (A269849 n))))) (else (+ 1 (* 2 (A270201 (A269850 n))))))) %Y A270201 Inverse: A270202. %Y A270201 Cf. A137264, A269849, A269850, A270189, A270190. %Y A270201 Similar permutation: A270193. %K A270201 nonn %O A270201 1,2 %A A270201 _Antti Karttunen_, Mar 16 2016