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 A253891 #9 Jan 17 2015 23:42:40 %S A253891 0,1,7,3,6,63,15,2,1023,32767,13,11,255,511,127,31,28,507,134217727, %T A253891 8388606,524287,17179869183,60,16777215,16383,8388607,65535,510,62, %U A253891 4095,4,14,1073741823,33554429,223,12855504354071922204335696738729300820177623950262342682411007,16381,268435451,19807040628566084398385987583,8589934589,55 %N A253891 Permutation of natural numbers: a(n) = A245611(A163511(n)). %C A253891 When A243071 is represented as a binary tree, then for any node A243071(k) containing n larger than zero, its left child A243071(2k-1) contains 1+(2*a(n)). %H A253891 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A253891 a(n) = A245611(A163511(n)). %F A253891 As a composition of other related permutations: %F A253891 a(n) = A054429(A253791(A054429(n))). %o A253891 (Scheme) (define (A253891 n) (A245611 (A163511 n))) %Y A253891 Inverse: A253892. %Y A253891 Similar permutations: A253791, A253883, A163511, A245611, A243071, A054429. %K A253891 nonn %O A253891 0,3 %A A253891 _Antti Karttunen_, Jan 17 2015