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A357964
Expansion of e.g.f. exp( (exp(x^3) - 1)/x^2 ).
3
1, 1, 1, 1, 13, 61, 181, 1261, 12601, 77113, 481321, 6102361, 63041221, 492260341, 6041807773, 87670198981, 945716793841, 11365316711281, 193962371184721, 2824572189001393, 36983289122143741, 658584258052917421, 12073641790111934341, 185876257572349699741
OFFSET
0,5
FORMULA
a(n) = n! * Sum_{k=0..floor(n/3)} Stirling2(n-2*k,n-3*k)/(n-2*k)!.
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp((exp(x^3)-1)/x^2)))
(PARI) a(n) = n!*sum(k=0, n\3, stirling(n-2*k, n-3*k, 2)/(n-2*k)!);
CROSSREFS
Cf. A353223.
Sequence in context: A127876 A361657 A308461 * A353223 A302560 A252970
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 22 2022
STATUS
approved