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 A375158 #6 Aug 01 2024 23:16:42
%S A375158 1,0,2,-1,2,0,2,0,0,0,2,1,2,-2,2,0,2,0,0,0,3,0,2,-2,2,0,2,0,0,2,2,0,0,
%T A375158 -2,2,0,3,0,2,0,2,0,2,-2,0,0,2,2,0,0,2,-1,4,-2,2,0,2,0,0,0,2,0,2,-2,2,
%U A375158 2,2,0,0,0,0,0,2,-2,4,1,2,0,0,0,0,0,2,0,4,0,2,0,0,-2,2,0,2,-2,2,0,1,0,2,0,4
%N A375158 Expansion of Sum_{k in Z} x^(2*k) / (1 - x^(7*k+2)).
%F A375158 G.f.: Product_{k>0} (1-x^(7*k))^2 * (1-x^(7*k-3)) * (1-x^(7*k-4)) / ((1-x^(7*k-2)) * (1-x^(7*k-5)))^2.
%o A375158 (PARI) my(N=110, x='x+O('x^N)); Vec(sum(k=-N, N, x^(2*k)/(1-x^(7*k+2))))
%o A375158 (PARI) my(N=110, x='x+O('x^N)); Vec(prod(k=1, N, (1-x^(7*k))^2*(1-x^(7*k-3))*(1-x^(7*k-4))/((1-x^(7*k-2))*(1-x^(7*k-5)))^2))
%Y A375158 Cf. A375107, A375148, A375159.
%Y A375158 Cf. A374900, A375108.
%K A375158 sign
%O A375158 0,3
%A A375158 _Seiichi Manyama_, Aug 01 2024