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Search: id:A059714
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| A059714 |
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Number of stacked directed animals on the triangular lattice. |
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+0
1
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| 1, 3, 11, 44, 184, 789, 3435, 15100, 66806, 296870, 1323318, 5911972, 26455294, 118528793, 531540891, 2385375732, 10710619014, 48112492938, 216195753066, 971744791032, 4368674392104, 19643610378738, 88339070102046
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Closely related to directed animals. A square lattice version exists.
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REFERENCES
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M. Bousquet-Melou and A. Rechnitzer, Lattice animals and heaps of dimers, Discrete Math. 258 (2002), no. 1-3, 235-274.
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LINKS
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M. Bousquet-Melou and A. Rechnitzer, Lattice animals and heaps of dimers
M. Bousquet-Melou and S. Butler, Forest-like permutations
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FORMULA
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G.f.: ((1-3x)(1-4x)-(1-5x)sqrt(1-4x))/(2x(2-9x))
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MAPLE
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gf := ((1-3*x)*(1-4*x)-(1-5*x)*sqrt(1-4*x))/(2*x*(2-9*x)): s := series(gf, x, 50): for i from 1 to 100 do printf(`%d, `, coeff(s, x, i)) od:
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CROSSREFS
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Cf. A005773.
Sequence in context: A012880 A149073 A167011 this_sequence A059715 A026748 A113174
Adjacent sequences: A059711 A059712 A059713 this_sequence A059715 A059716 A059717
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KEYWORD
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nonn
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AUTHOR
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Mireille Bousquet-Melou (bousquet(AT)labri.u-bordeaux.fr), Feb 08 2001
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Feb 09 2001
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