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 A038069 #16 Jun 23 2018 15:25:47
%S A038069 4,-6,20,-66,204,-670,2340,-8226,29120,-104754,381300,-1398410,
%T A038069 5162220,-19172790,71582716,-268439586,1010580540,-3817733920,
%U A038069 14467258260,-54975633702,209430785460,-799644629550,3059510616420
%N A038069 Product_{k>=1} ((1 + x^k)^a(k)) = 1 + 4x.
%H A038069 Seiichi Manyama, <a href="/A038069/b038069.txt">Table of n, a(n) for n = 1..1000</a>
%H A038069 N. J. A. Sloane, <a href="/transforms.txt">Weigh transform</a>
%F A038069 Dirichlet convolution of A038065 with characteristic function of powers of 2.
%F A038069 a(n) = (1/n)*(-(-4)^n + Sum_{d<n and d|n} (-1)^(n/d)*d*a(d)). - _Seiichi Manyama_, Jun 23 2018
%Y A038069 Cf. A038063-A038070, A306158.
%K A038069 sign
%O A038069 1,1
%A A038069 _Christian G. Bower_, Jan 04 1999