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A006572
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Numerators of an asymptotic expansion for the number of forests on n nodes (A001858).
(Formerly M3817)
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3
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0, 0, 1, 5, 11, -203, -17207, -3607, 1408301, 8181503, -3299598169, -14983154641, -449428440959, 2480887997789, 19076621521399973, -31806561859970819, -3485566370059659659, -2180443004193000007, 54188073629843061671671
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OFFSET
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0,4
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COMMENTS
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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).
L. Takacs, On the number of distinct forests, SIAM J. Discrete Math., 3 (1990), 574-581.
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LINKS
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FORMULA
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a(n) = numerator(Sum_{i=1..floor(n/2)} (-1)^(i-1) * |A111999(n, 2*i-1)| / (2^(n-i) * (n-i)!)). - Sean A. Irvine, May 11 2017
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CROSSREFS
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KEYWORD
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sign,frac
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AUTHOR
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EXTENSIONS
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a(10) and a(11) corrected and more terms from Sean A. Irvine, May 11 2017
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STATUS
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approved
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