

A005198


a(n) is the number of forests with n (unlabeled) nodes in which each component tree is planted, that is, is a rooted tree in which the root has degree 1.
(Formerly M2491)


0



0, 1, 1, 3, 5, 13, 27, 68, 160, 404, 1010, 2604, 6726, 17661, 46628, 124287, 333162, 898921, 2437254, 6640537, 18166568, 49890419, 137478389, 380031868, 1053517588, 2928246650, 8158727139, 22782938271, 63752461474
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OFFSET

1,4


REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

Table of n, a(n) for n=1..29.
E. M. Palmer and A. J. Schwenk, On the number of trees in a random forest, J. Combin. Theory, B 27 (1979), 109121.


CROSSREFS

Sequence in context: A000631 A026569 A035082 * A160823 A077443 A147196
Adjacent sequences: A005195 A005196 A005197 * A005199 A005200 A005201


KEYWORD

nonn


AUTHOR

N. J. A. Sloane. Definition clarified and more terms added from PalmerSchwenk by N. J. A. Sloane, May 29 2012


STATUS

approved



