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A006544
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Number of stable forests with n nodes.
(Formerly M0702)
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3
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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
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0,3
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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K. L. McAvaney, Counting stable trees, pp. 79-85 of Combinatorial Mathematics (Proceedings 2nd Australian Conf.), Lect. Notes Math. 403, 1974.
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FORMULA
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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
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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