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A265059 Coordination sequence for (2,3,9) tiling of hyperbolic plane. 27
1, 3, 5, 7, 9, 12, 16, 21, 28, 36, 45, 56, 70, 89, 113, 143, 181, 228, 287, 361, 455, 575, 726, 916, 1155, 1456, 1836, 2315, 2920, 3684, 4647, 5861, 7391, 9321, 11756, 14827, 18701, 23587, 29749, 37520, 47320, 59681, 75272, 94936, 119737, 151016, 190466, 240221, 302973, 382119, 481941, 607840, 766627 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

J. W. Cannon, P. Wagreich, Growth functions of surface groups, Mathematische Annalen, 1992, Volume 293, pp. 239-257. See Prop. 3.1.

FORMULA

G.f.: (x+1)^2*(x^2+x+1)*(x^6+x^3+1)/(x^10-x^8-x^5-x^2+1).

MATHEMATICA

CoefficientList[Series[(x + 1)^2 (x^2 + x + 1) (x^6 + x^3 + 1)/(x^10 - x^8 - x^5 - x^2 + 1), {x, 0, 60}], x] (* Vincenzo Librandi, Dec 30 2015 *)

PROG

(PARI) x='x+O('x^50); Vec((x+1)^2*(x^2+x+1)*(x^6+x^3+1)/(x^10-x^8-x^5-x^2+1)) \\ G. C. Greubel, Aug 06 2017

CROSSREFS

Coordination sequences for triangular tilings of hyperbolic space: A001630, A007283, A054886, A078042, A096231, A163876, A179070, A265057, A265058, A265059, A265060, A265061, A265062, A265063, A265064, A265065, A265066, A265067, A265068, A265069, A265070, A265071, A265072, A265073, A265074, A265075, A265076, A265077.

Sequence in context: A122643 A194240 A265058 * A096231 A100432 A261033

Adjacent sequences:  A265056 A265057 A265058 * A265060 A265061 A265062

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Dec 29 2015

STATUS

approved

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Last modified November 15 11:35 EST 2018. Contains 317238 sequences. (Running on oeis4.)