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 A331144 Irregular triangle read by rows: row n gives coefficients (in increasing order of powers of x) of normalized numerator polynomial of generating function for hexagonal lattice directed site animals. Here n is the number of sites supported in one particular way. 0
 1, 1, 1, 1, 1, 1, 2, 4, 2, 0, 1, 1, 3, 4, 10, 12, 14, 16, 13, 14, 7, 6, 4, 0, 1, 1, 4, 8, 22, 37, 56, 88, 98, 137, 118, 145, 113, 104, 79, 50, 40, 17, 10, 6, 0, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,7 COMMENTS Guttmann-Conway give coefficients for rows n <= 9. This triangle just gives the numerators of the generating functions. Although it is not clear from their descriptions, it appears that A055907-A055915 give the expansions of the actual generating functions. REFERENCES Guttmann, A. J., and A. R. Conway. "Hexagonal lattice directed site animals." Series on advances in statistical mechanics, 14.1 (1999): 491-504. LINKS A. J., Guttmann and A. R. Conway, Hexagonal lattice directed site animals, preprint, 1999. EXAMPLE Triangle begins: 1, 1, 1,1,1, 1,2,4,2,0,1, 1,3,4,10,12,14,16,13,14,7,6,4,0,1, 1,4,8,22,37,56,88,98,137,118,145,113,104,79,50,40,17,10,6,0,1 ... CROSSREFS Cf. A055907-A055915. Sequence in context: A318222 A209466 A277659 * A258711 A127278 A335764 Adjacent sequences:  A331141 A331142 A331143 * A331145 A331146 A331147 KEYWORD nonn,tabf,more AUTHOR N. J. A. Sloane, Jan 13 2020 STATUS approved

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Last modified August 14 01:28 EDT 2020. Contains 336473 sequences. (Running on oeis4.)