A346968 E.g.f.: 1 / (2 - exp(x + x^2/2)).

1, 1, 4, 22, 162, 1486, 16368, 210316, 3088564, 51025900, 936661728, 18913304488, 416620504248, 9942050541736, 255502984674304, 7035244770121168, 206628950531763120, 6448104490837364176, 213057362719338692736, 7430912083404422167264, 272812392358000969636000

Offset

0,3

Links

Table of n, a(n) for n=0..20.

Formula

a(0) = 1; a(n) = Sum_{k=1..n} binomial(n,k) * A000085(k) * a(n-k).

a(n) ~ n! / (2 * sqrt(1 + 2*log(2)) * (sqrt(1 + 2*log(2)) - 1)^(n+1)). - Vaclav Kotesovec, Aug 15 2021

Mathematica

nmax = 20; CoefficientList[Series[1/(2 - Exp[x + x^2/2]), {x, 0, nmax}], x] Range[0, nmax]!

Crossrefs

Cf. A000085, A346967.

Sequence in context: A122704 A087547 A218678 * A184942 A000779 A053144

Adjacent sequences: A346965 A346966 A346967 * A346969 A346970 A346971

Keyword

nonn

Author

Ilya Gutkovskiy, Aug 09 2021

Status

approved