A361489 Expansion of e.g.f. exp(exp(x) - 1 + x^3/6).

1, 1, 2, 6, 19, 72, 313, 1472, 7612, 42679, 255515, 1632710, 11065057, 79065807, 594174922, 4679473130, 38500353667, 330172915164, 2944613004359, 27253908250340, 261328607398332, 2591724561444621, 26545170005412613, 280411070646125638

Offset

0,3

Links

Table of n, a(n) for n=0..23.

Formula

a(0) = a(1) = 1, a(2) = 2; a(n) = binomial(n-1,2) * a(n-3) + Sum_{k=1..n} binomial(n-1,k-1) * a(n-k).

Prog

(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(exp(x)-1+x^3/6)))

Crossrefs

Cf. A124504, A360991.

Sequence in context: A150118 A343417 A150119 * A378586 A268569 A181770

Adjacent sequences: A361486 A361487 A361488 * A361490 A361491 A361492

Keyword

nonn,easy

Author

Seiichi Manyama, Mar 14 2023

Status

approved