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 A140130 #14 Jun 30 2021 05:30:18 %S A140130 1,1,1,1,2,1,1,1,4,2,4,1,2,1,1,1,8,4,8,2,8,4,8,1,4,2,4,1,2,1,1,1,16,8, %T A140130 16,4,16,8,16,2,16,8,16,4,16,8,16,1,8,4,8,2,8,4,8,1,4,2,4,1,2,1,1,1, %U A140130 32,16,32,8,32,16,32,4,32,16,32,8,32,16,32,2,32,16,32,8,32,16,32,4,32,16 %N A140130 a(n) = denominator(c(n)) where c(n) = 1 if n=1, otherwise if n < 3*2^floor(log_2(n)-1) then c(n) = (c(floor(n/2))+c(floor((n+1)/2)))/2 otherwise c(n) = c(n-2^floor(log_2(n)))+1. %C A140130 See A140129 for further comments and examples. %H A140130 Reinhard Zumkeller, <a href="/A140130/b140130.txt">Table of n, a(n) for n = 1..8191</a> %F A140130 a(n) = if n=1 then 1 else if n < 3*2^floor(log_2(n)-1) then (if n mod 2 = 0 then a(n/2) else 2^floor(log_2(n)-1)) else a(n-floor(log_2(n))). %F A140130 For n>1: a(A023758(n)) = 1. %Y A140130 Cf. A140129 (numerators). %K A140130 nonn,frac %O A140130 1,5 %A A140130 _Reinhard Zumkeller_, May 14 2008