A337186 a(n) = 1 + Sum_{k=0..n-2} binomial(n-2,k) * a(k).

1, 1, 2, 3, 6, 14, 36, 101, 308, 1013, 3562, 13300, 52482, 218045, 950614, 4335563, 20628882, 102153978, 525383324, 2801105889, 15455435864, 88117352141, 518391612686, 3142762585120, 19611454375090, 125829007917417, 829254498014570, 5608225148263459

Offset

0,3

Links

Table of n, a(n) for n=0..27.

Formula

G.f. A(x) satisfies: A(x) = (1/(1 - x)) * (1 + x^2 * A(x/(1 - x))).

Mathematica

a[n_] := a[n] = 1 + Sum[Binomial[n - 2, k] a[k], {k, 0, n - 2}]; Table[a[n], {n, 0, 27}]

Crossrefs

Cf. A000994, A007476, A186021.

Sequence in context: A319323 A341630 A001420 * A049339 A157100 A081293

Adjacent sequences: A337183 A337184 A337185 * A337187 A337188 A337189

Keyword

nonn

Author

Ilya Gutkovskiy, Jan 29 2021

Status

approved