OFFSET
0,5
REFERENCES
Miklos Bona, Introduction to Enumerative and Analytic Combinatorics, CRC Press, 2025, p. 412.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..450
FORMULA
E.g.f.: exp(-x^2/2-x^3/3)/(1 - x).
a(n) ~ A394996*n!.
MAPLE
a:= proc(n) option remember; `if`(n=0, 1, add(
a(n-j)*(j-1)!*binomial(n-1, j-1), j=[1, $4..n]))
end:
seq(a(n), n=0..23); # Alois P. Heinz, Apr 10 2026
MATHEMATICA
terms=24; CoefficientList[Series[Exp[-x^2/2-x^3/3]/(1-x), {x, 0, terms-1}], x]*Range[0, terms-1]!
CROSSREFS
KEYWORD
nonn,new
AUTHOR
Stefano Spezia, Apr 09 2026
STATUS
approved