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A265066 Coordination sequence for (2,5,7) tiling of hyperbolic plane. 27
1, 3, 5, 8, 13, 20, 30, 45, 67, 100, 149, 221, 329, 491, 731, 1087, 1618, 2409, 3586, 5338, 7946, 11828, 17607, 26209, 39013, 58074, 86448, 128683, 191552, 285138, 424447, 631817, 940501, 1399997, 2083987, 3102151, 4617754, 6873828, 10232143, 15231214, 22672656, 33749729, 50238677, 74783553, 111320204, 165707396 (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^6+x^5+x^4+x^3+x^2+x+1)*(x^4+x^3+x^2+x+1)*(x+1)^2/(x^12+x^11-x^9-2*x^8-3*x^7-3*x^6-3*x^5-2*x^4-x^3+x+1).

MATHEMATICA

CoefficientList[Series[(x^6 + x^5 + x^4 + x^3 + x^2 + x + 1) (x^4 + x^3 + x^2 + x + 1) (x + 1)^2 / (x^12 + x^11 - x^9 - 2 x^8 - 3 x^7 - 3 x^6 - 3 x^5 - 2 x^4 - x^3 + x + 1), {x, 0, 45}], x] (* Vincenzo Librandi, Jan 20 2016 *)

PROG

(PARI) Vec((x^6+x^5+x^4+x^3+x^2+x+1)*(x^4+x^3+x^2+x+1)*(x+1)^2/(x^12+x^11-x^9-2*x^8-3*x^7-3*x^6-3*x^5-2*x^4-x^3+x+1) + O(x^50)) \\ Michel Marcus, Jan 20 2016

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: A245934 A099351 A265065 * A265067 A265068 A227547

Adjacent sequences:  A265063 A265064 A265065 * A265067 A265068 A265069

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 29 2015

STATUS

approved

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Last modified April 11 09:54 EDT 2021. Contains 342886 sequences. (Running on oeis4.)