

A006544


Number of stable forests with n nodes.
(Formerly M0702)


3



1, 1, 2, 3, 5, 8, 15, 27, 54, 110, 238, 526, 1211, 2839, 6825, 16655, 41315, 103663, 263086, 673604, 1739155, 4521632, 11831735, 31134338, 82352098, 218837877, 584018065, 1564679863, 4207224730, 11350583175, 30718054693, 83373960954, 226907180850, 619118327796
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OFFSET

0,3


REFERENCES

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


LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..1000
K. L. McAvaney, Counting stable trees, pp. 7985 of Combinatorial Mathematics (Proceedings 2nd Australian Conf.), Lect. Notes Math. 403, 1974.
K. L. McAvaney, Letter to N. J. A. Sloane, May 1975


FORMULA

G.f.: Sum_{n>=1} Z(S_n,s(x)) where s(x) is the g.f. for A003426 and Z(S_n) is the cycle index of the symmetric group on n elements.  Sean A. Irvine, Feb 13 2016


CROSSREFS

Cf. A006545, A003426, A003427, A003428, A003429.
Sequence in context: A000047 A101172 A192677 * A110536 A049861 A130476
Adjacent sequences: A006541 A006542 A006543 * A006545 A006546 A006547


KEYWORD

nonn


AUTHOR

N. J. A. Sloane.


EXTENSIONS

More terms from Sean A. Irvine, Feb 13 2016


STATUS

approved



