A265062 Coordination sequence for (2,4,7) tiling of hyperbolic plane.

1, 3, 5, 8, 12, 17, 25, 36, 50, 70, 98, 137, 193, 271, 379, 531, 744, 1042, 1461, 2048, 2869, 4020, 5633, 7893, 11061, 15500, 21719, 30434, 42646, 59758, 83738, 117340, 164424, 230402, 322855, 452406, 633943, 888325, 1244781, 1744272, 2444193, 3424970, 4799303, 6725112, 9423686, 13205113, 18503907, 25928939, 36333403

Offset: 0

Author

N. J. A. Sloane, Dec 29 2015

Keywords

• nonn
• easy

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.
• Index entries for linear recurrences with constant coefficients, signature (0,0,1,1,1,1,1,0,0,-1).

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.

Programs

Mathematica

CoefficientList[Series[(x + 1)^2 (x^2 + 1) (x^6 + x^5 + x^4 + x^3 + x^2 + x + 1)/(x^10 - x^7 - x^6 - x^5 - x^4 - x^3 + 1), {x, 0, 50}], x] (* Vincenzo Librandi, Dec 31 2015 *)
LinearRecurrence[{0,0,1,1,1,1,1,0,0,-1},{1,3,5,8,12,17,25,36,50,70,98},50] (* Harvey P. Dale, May 17 2023 *)

PARI

Vec((x+1)^2*(x^2+1)*(x^6+x^5+x^4+x^3+x^2+x+1)/(x^10-x^7-x^6-x^5-x^4-x^3+1) + O(x^50)) \\ Michel Marcus, Dec 31 2015

Formula

G.f.: (x+1)^2*(x^2+1)*(x^6+x^5+x^4+x^3+x^2+x+1)/(x^10-x^7-x^6-x^5-x^4-x^3+1).