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A053490 E.g.f.: (1-x)^(-3x). 2
1, 0, 6, 9, 132, 630, 6642, 55440, 608976, 6790392, 85413960, 1145077560, 16600386888, 256806229680, 4233767671728, 74015194485960, 1368023697469440, 26649263762049600, 545697922821501888, 11717708270380421760, 263276186128105633920 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

REFERENCES

R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Example 5.2.3.

FORMULA

a(n) = (-1)^n*Sum_{k=0..floor(n/2)} 3^k*binomial(n, k)*k!*Stirling1(n-k, k). - Vladeta Jovovic (vladeta(AT)eunet.rs), Dec 19 2004

CROSSREFS

A007113, A053489.

Sequence in context: A121233 A156180 A191011 * A061110 A110460 A159190

Adjacent sequences:  A053487 A053488 A053489 * A053491 A053492 A053493

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Jan 15 2000

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Last modified February 13 18:14 EST 2012. Contains 205534 sequences.