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 A075159 #6 May 01 2014 02:44:54 %S A075159 1,2,3,4,6,5,9,8,12,15,7,10,18,25,27,16,24,45,35,30,14,11,21,20,36,75, %T A075159 49,50,54,125,81,32,48,135,175,90,70,77,105,60,28,33,13,22,42,55,63, %U A075159 40,72,225,245,150,98,121,147,100,108,375,343,250,162,625,243,64,96,405 %N A075159 Run lengths in the binary expansion of n-1 gives the vector of exponents in prime factorization of a(n), with the least significant run corresponding to the exponent of the least prime, 2. %C A075159 To make this a permutation of nonnegative integers, we subtract one from each run count except for the most significant run, e.g. a(12) = 10, as 12-1 = 11 = 1011 and 10 = 5^1 * 3^(1-1) * 2^(2-1). %H A075159 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %Y A075159 Inverse of A075160. a(n) = A075157(n-1)+1. %K A075159 nonn %O A075159 1,2 %A A075159 _Antti Karttunen_, Sep 13 2002