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 A113240 #2 Mar 30 2012 18:59:12
%S A113240 1,2,5,6,13,14,25,30,49,50,97,98,165,186,325,326,621,622,1161,1230,
%T A113240 2257,2258,4481,4498,8597,8858,17125,17126,34077,34078,66985,68014,
%U A113240 133553,133634,267057,267058,529205,533306,1058261,1058262,2115133
%N A113240 Expansion of (1/(1-x))*sum(k>=2,x^k/(1-2x^k)).
%F A113240 a(n)=sum{k=0..floor(n/2), floor((n-k+1)/(k+1))*2^k}.
%Y A113240 Cf. A002541.
%K A113240 easy,nonn
%O A113240 0,2
%A A113240 _Paul Barry_, Oct 19 2005