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 A180125 #4 Jun 02 2025 03:02:44
%S A180125 0,1,0,2,2,3,2,5,2,5,2,6,4,7,4,10,6,9,6,12,8,11,8,15,8,13,8,16,10,15,
%T A180125 10,21,10,17,10,20,12,19,12,25,12,21,12,24,14,23,14,30,16,25,16,30,18,
%U A180125 27,18,35,18,29,18,34,20,31,20,42,22,33,22,40,24,35,24,45,24,37
%N A180125 Self-convolution of period-doubling sequence A035263.
%C A180125 Reducing a(n) mod 2 gives 1-A035263(n), which is also A096268(n+1).
%F A180125 a(n) = sum(b(i)b(n-i), i=1..(n-1)), where b(i)=A035263(i).
%t A180125 b[i_] := b[i] = If[OddQ[i], 1, 1 - b[i/2]]; a[n_] := Sum[b[i] b[n - i], {i, 1, n - 1}]
%Y A180125 Cf. A035263, A096268
%K A180125 nonn
%O A180125 1,4
%A A180125 _Jacob A. Siehler_, Aug 11 2010