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A357922
a(n) = Sum_{k=0..floor(n/5)} |Stirling1(n - 4*k,k)|.
0
1, 0, 0, 0, 0, 1, 1, 2, 6, 24, 121, 723, 5051, 40370, 363154, 3630565, 39929874, 479111219, 6228047601, 87188921464, 1307794924973, 20924276449014, 355707232027825, 6402657184129671, 121649439722758345, 2432972744390660437, 51092165603897459951
OFFSET
0,8
FORMULA
G.f.: Sum_{k>=0} x^k * Product_{j=0..k-1} (j + x^4).
PROG
(PARI) a(n) = sum(k=0, n\5, abs(stirling(n-4*k, k, 1)));
(PARI) my(N=30, x='x+O('x^N)); Vec(sum(k=0, N, x^k*prod(j=0, k-1, j+x^4)))
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 20 2022
STATUS
approved