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 A245611 #13 Jul 31 2014 23:50:34 %S A245611 0,1,3,7,2,15,31,6,63,127,14,255,5,4,511,1023,30,13,2047,62,4095,8191, %T A245611 12,16383,11,126,32767,29,254,65535,131071,28,61,262143,510,524287, %U A245611 1048575,10,27,2097151,8,4194303,125,1022,8388607,59,2046,253,16777215,60,33554431,67108863,26 %N A245611 Permutation of natural numbers: a(n) = A243071(A064216(n)). %C A245611 Note the indexing: the domain starts from 1, while the range includes also zero. %C A245611 The odd bisection of A243071 decremented by one and halved. (For a(1) = 0, take ceiling of -1/2). %H A245611 Antti Karttunen, <a href="/A245611/b245611.txt">Table of n, a(n) for n = 1..1024</a> %H A245611 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A245611 a(1) = 0, and for n > 1, a(n) = (1/2) * (A243071((2*n)-1) - 1). %F A245611 As a composition of related permutations: %F A245611 a(n) = A243071(A064216(n)). %F A245611 a(n) = A054429(A244153(n)). %o A245611 (Scheme) (define (A245611 n) (A243071 (A064216 n))) ;; offset 1, a(1) = 0. %Y A245611 Inverse: A245612. %Y A245611 Cf. A054429, A064216, A243071, A243065-A243066, A243505-A243506, A245607, A245609, A244153, A244154. %K A245611 nonn %O A245611 1,3 %A A245611 _Antti Karttunen_, Jul 28 2014