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 A055907 Triangle: number of directed site animals on hexagonal net (honeycomb) with n total sites and k sites supported in one particular way. 11
 0, 1, 1, 1, 2, 1, 1, 4, 4, 1, 1, 6, 10, 6, 1, 1, 9, 21, 20, 8, 1, 1, 12, 39, 53, 36, 10, 1, 1, 16, 67, 121, 128, 56, 12, 1, 1, 20, 107, 249, 388, 240, 74, 14, 1, 1, 25, 163, 471, 1050, 854, 331, 100, 16, 1, 1, 30, 238, 836, 2601, 2654, 1212, 511, 130, 18, 1, 1, 36, 337 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 LINKS Table of n, a(n) for n=0..68. A. J. Guttmann, Indicators of solvability for lattice models, Discrete Math., 217 (2000), 167-189 (A_h of Section 6). A. J. Guttmann and A. R. Conway, Hexagonal lattice directed site animals, Statistical Physics on the Eve of the Twenty-First Century, ed. M. T. Batchelor, World Scientific, 1999 (F_h of Section 4). EXAMPLE Table begins: 0; 1, 1; 1, 2, 1; 1, 4, 4, 1; 1, 6, 10, 6, 1; ... CROSSREFS Row sums give A055919. Columns 1-9 give: A002620(n+1), A055908, A055909, A055910, A055911, A055912, A055913, A055914, A055915. Cf. A055898. Sequence in context: A157528 A132731 A128966 * A259698 A274643 A172991 Adjacent sequences: A055904 A055905 A055906 * A055908 A055909 A055910 KEYWORD nonn,tabl AUTHOR Christian G. Bower, Jun 14 2000 EXTENSIONS Name edited by Andrey Zabolotskiy, Jun 21 2022 STATUS approved

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Last modified September 7 13:22 EDT 2024. Contains 375730 sequences. (Running on oeis4.)