This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A265066 #18 Feb 22 2025 22:25:44
%S A265066 1,3,5,8,13,20,30,45,67,100,149,221,329,491,731,1087,1618,2409,3586,
%T A265066 5338,7946,11828,17607,26209,39013,58074,86448,128683,191552,285138,
%U A265066 424447,631817,940501,1399997,2083987,3102151,4617754,6873828,10232143,15231214,22672656,33749729,50238677,74783553,111320204,165707396
%N A265066 Coordination sequence for (2,5,7) tiling of hyperbolic plane.
%H A265066 G. C. Greubel, <a href="/A265066/b265066.txt">Table of n, a(n) for n = 0..1000</a>
%H A265066 J. W. Cannon, P. Wagreich, <a href="http://dx.doi.org/10.1007/BF01444714">Growth functions of surface groups</a>, Mathematische Annalen, 1992, Volume 293, pp. 239-257. See Prop. 3.1.
%H A265066 <a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (-1, 0, 1, 2, 3, 3, 3, 2, 1, 0, -1, -1).
%F A265066 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).
%t A265066 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 *)
%o A265066 (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
%Y A265066 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.
%K A265066 nonn,easy
%O A265066 0,2
%A A265066 _N. J. A. Sloane_, Dec 29 2015