A370699 Expansion of e.g.f. exp(-x^3/6)/(1-x).
1, 1, 2, 5, 20, 100, 610, 4270, 34160, 307160, 3071600, 33787600, 405466600, 5271065800, 73794921200, 1106922416600, 17710758665600, 301082897315200, 5419492342264000, 102970354503016000, 2059407090060320000, 43247548855054544000, 951446074811199968000
Offset: 0
Programs
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PARI
my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(-x^3/6)/(1-x))) -
PARI
a(n) = n!*sum(k=0, n\3, (-1)^k/(6^k*k!));
Formula
a(n) = n! * Sum_{k=0..floor(n/3)} (-1)^k/(6^k * k!).