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 A306691 #30 Aug 03 2020 19:25:37
%S A306691 1,1,0,1,-1,1,0,-1,1,0,0,-2,4,-4,3,-2,0,2,-1,-2,3,-1,-3,8,-11,10,-8,9,
%T A306691 -13,15,-9,-2,6,2,-14,21,-20,10,8,-25,29,-22,20,-31,46,-53,48,-33,15,
%U A306691 -9,27,-57,71,-62,53,-63,83,-87,53,16,-80,91,-47,3,-19,99,-186,219,-184
%N A306691 Expansion of Product_{k>=1} (1 + x^k * (1 - x)).
%H A306691 Seiichi Manyama, <a href="/A306691/b306691.txt">Table of n, a(n) for n = 0..1000</a>
%F A306691 G.f.: exp(Sum_{k>=1} x^k * Sum_{d|k} (-1)^(d+1)*(1 - x)^d/d). - _Ilya Gutkovskiy_, Apr 16 2019
%t A306691 With[{nn=70},CoefficientList[Series[Product[1+x^k (1-x),{k,nn}],{x,0,nn}],x]] (* _Harvey P. Dale_, Aug 03 2020 *)
%o A306691 (PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, 1+x^k*(1-x)))
%Y A306691 Cf. A160571, A198197, A306565, A306749.
%K A306691 sign
%O A306691 0,12
%A A306691 _Seiichi Manyama_, Apr 16 2019