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A059715
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Number of multi-directed animals on the triangular lattice.
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0
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1, 3, 11, 44, 184, 790, 3450, 15242, 67895, 304267, 1369761, 6188002, 28031111, 127253141, 578694237, 2635356807, 12015117401, 54831125131, 250418753498, 1144434017309
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Counts certain animals that generalize directed animals. They are also equinumerous with a class of n-ominoes studied by Klarner in 1967.
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REFERENCES
| M. Bousquet-Melou and A. Rechnitzer, Lattice animals and heaps of dimers, Discrete Math. 258 (2002), no. 1-3, 235-274.
D. A. Klarner, Cell growth problems, Canad. J. Math. 19 (1967) 851-863.
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LINKS
| M. Bousquet-Melou and A. Rechnitzer, Lattice animals and heaps of dimers
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FORMULA
| The generating function is known in closed form. It is big and non-D-finite.
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CROSSREFS
| Cf. A005773.
Sequence in context: A149073 A167011 A059714 * A026748 A113174 A132840
Adjacent sequences: A059712 A059713 A059714 * A059716 A059717 A059718
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KEYWORD
| nonn
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AUTHOR
| Mireille Bousquet-Melou (bousquet(AT)labri.u-bordeaux.fr), Feb 08 2001
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