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A373335 Expansion of Sum_{k>=1} x^k / (1 + x^k + x^(2*k) + x^(3*k) + x^(4*k)).

%I A373335 #14 Jun 01 2024 11:40:46
%S A373335 1,0,1,0,1,1,0,0,1,0,2,0,1,-1,1,1,0,1,1,0,1,0,1,0,1,1,0,-1,1,1,2,0,2,
%T A373335 -1,0,1,0,0,1,0,2,0,1,0,1,1,0,1,0,0,1,0,1,0,2,0,0,0,1,0,2,0,1,0,1,2,0,
%U A373335 -1,1,-1,2,0,1,-1,1,1,0,2,1,1,1,0,1,-1,0,1,0,0,1,1,1,0,2,-1,1,1,0,-1,2,0,2
%N A373335 Expansion of Sum_{k>=1} x^k / (1 + x^k + x^(2*k) + x^(3*k) + x^(4*k)).
%H A373335 Seiichi Manyama, <a href="/A373335/b373335.txt">Table of n, a(n) for n = 1..10000</a>
%F A373335 G.f.: Sum_{k>=1} x^k * (1 - x^k) / (1 - x^(5*k)).
%F A373335 a(n) = A001876(n) - A001877(n).
%o A373335 (PARI) my(N=110, x='x+O('x^N)); Vec(sum(k=1, N, x^k*(1-x^k)/(1-x^(5*k))))
%o A373335 (PARI) a(n) = sumdiv(n, d, (d%5==1)-(d%5==2));
%Y A373335 Cf. A002324, A048272, A373336.
%Y A373335 Cf. A001876, A001877.
%K A373335 sign,easy
%O A373335 1,11
%A A373335 _Seiichi Manyama_, Jun 01 2024