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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
OFFSET
0,2
LINKS
J. W. Cannon, P. Wagreich, Growth functions of surface groups, Mathematische Annalen, 1992, Volume 293, pp. 239-257. See Prop. 3.1.
Index entries for linear recurrences with constant coefficients, signature (0, 1, 0, 0, 1, 0, 0, 1, 0, -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
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Dec 29 2015
STATUS
approved