A144958 A005195(n) - A005195(n-1).

0, 1, 1, 3, 4, 10, 17, 39, 77, 176, 381, 891, 2057, 4941, 11915, 29391, 73058, 184236, 468330, 1202349, 3108760, 8097518, 21218776, 55925742, 148146312, 394300662, 1053929982, 2828250002, 7617271738, 20584886435, 55802753243

Offset

1,4

Comments

a(n) is the number of forests with n unlabeled nodes without isolated vertices. This follows from the fact that for n>0 A005195(n-1) counts the forests with one or more isolated nodes.

Links

Table of n, a(n) for n=1..31.

Crossrefs

Cf. A005195, A144959.

Sequence in context: A172416 A317883 A337089 * A034775 A280246 A338012

Adjacent sequences: A144955 A144956 A144957 * A144959 A144960 A144961

Keyword

nonn

Author

Washington Bomfim, Sep 27 2008

Status

approved