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 A307626 #15 May 14 2021 02:52:51
%S A307626 1,1,1,1,2,1,4,0,8,-3,16,-12,36,-40,88,-117,220,-321,560,-860,1447,
%T A307626 -2284,3772,-6032,9861,-15864,25798,-41627,67527,-109132,176826,
%U A307626 -285985,463089,-749189,1212722,-1962181,3175635,-5138421,8315361,-13455103,21772865
%N A307626 Expansion of Product_{k>=1} 1/(1 - x^k/(1 + x)).
%H A307626 Seiichi Manyama, <a href="/A307626/b307626.txt">Table of n, a(n) for n = 0..500</a>
%F A307626 G.f.: exp(Sum_{k>=1} x^k * Sum_{d|k} 1/(d*(1+x)^d)).
%t A307626 m = 40; CoefficientList[Series[Product[1/(1 - x^k/(1 + x)), {k, 1, m}], {x, 0, m}], x] (* _Amiram Eldar_, May 14 2021 *)
%o A307626 (PARI) N=66; x='x+O('x^N); Vec(1/prod(k=1, N, 1-x^k/(1+x)))
%o A307626 (PARI) N=66; x='x+O('x^N); Vec(exp(sum(k=1, N, x^k*sumdiv(k, d, 1/(d*(1+x)^d)))))
%Y A307626 Convolution inverse A307601.
%Y A307626 Cf. A227682.
%K A307626 sign
%O A307626 0,5
%A A307626 _Seiichi Manyama_, Apr 19 2019