A357920 a(n) = Sum_{k=0..floor(n/5)} Stirling1(n - 4*k,k).
1, 0, 0, 0, 0, 1, -1, 2, -6, 24, -119, 717, -5029, 40270, -362606, 3627037, -39903738, 478892051, -6225994449, 87167664184, -1307553837291, 20921303563234, -355667626509575, 6402090252833481, -121640761396741607, 2432831275825738669, -51089718792714854191
Offset: 0
Keywords
Programs
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PARI
a(n) = sum(k=0, n\5, stirling(n-4*k, k, 1));
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PARI
my(N=30, x='x+O('x^N)); Vec(sum(k=0, N, (-x)^k*prod(j=0, k-1, j-x^4)))
Formula
G.f.: Sum_{k>=0} (-x)^k * Product_{j=0..k-1} (j - x^4).