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A047750
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If n mod 2 = 0 then m := n/2 and a(n) = (3*m)!*(5*m+1)/((m+1)!*(2*m+1)!); otherwise m := (n-1)/2, a(n) = 6*(3*m+2)!/(m!*(2*m+3)!).
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2
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1, 2, 3, 6, 11, 24, 48, 110, 231, 546, 1183, 2856, 6324, 15504, 34884, 86526, 197087, 493350, 1134705, 2861430, 6633315, 16829280, 39268320, 100134216, 234930276, 601661144, 1418201268, 3645533040, 8627761528, 22249511328
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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REFERENCES
| L. W. Beineke and R. E. Pippert, Enumerating dissectable polyhedra by their automorphism groups, Canad. J. Math., 26 (1974), 50-67.
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FORMULA
| a(n) = sum of top row terms in M^n, M = the infinite square poduction matrix:
1, 1, 0, 0, 0, 0,...
0, 0, 1, 0, 0, 0,...
1, 1, 0, 1, 0, 0,...
0, 0, 1, 0, 1, 0,...
1, 1, 0, 1, 0, 1,...
...
- Gary W. Adamson, Jul 14 2011
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CROSSREFS
| Sequence in context: A176425 A000992 A036648 * A072187 A122852 A072374
Adjacent sequences: A047747 A047748 A047749 * A047751 A047752 A047753
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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