A006544 Number of stable forests with n nodes. (Formerly M0702)

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

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. 79-85 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: A101172 A192677 A307909 * A110536 A049861 A130476

Adjacent sequences: A006541 A006542 A006543 * A006545 A006546 A006547

Keyword

nonn,changed

Author

N. J. A. Sloane

Extensions

More terms from Sean A. Irvine, Feb 13 2016

Status

approved