A001360 Crystal ball sequence for hyperbolic tessellation 3^7 (from triangle group (2,3,7)).

1, 8, 29, 85, 232, 617, 1625, 4264, 11173, 29261, 76616, 200593, 525169, 1374920, 3599597, 9423877, 24672040, 64592249, 169104713, 442721896, 1159060981, 3034461053, 7944322184, 20798505505, 54451194337, 142555077512, 373214038205, 977087037109, 2558047073128, 6697054182281, 17533115473721, 45902292238888

Offset

0,2

Links

Georg Fischer, Table of n, a(n) for n = 0..1000

Index entries for crystal ball sequences

Index entries for linear recurrences with constant coefficients, signature (4,-4,1).

Formula

a(n) = 4*a(n-1)-4*a(n-2)+a(n-3). G.f.: (1+4*x+x^2)/((1-x)*(1-3*x+x^2)): partial sums of A001354. - Colin Barker, Mar 16 2012

Mathematica

 LinearRecurrence[{4, -4, 1}, {1, 8, 29}, 32] (* Georg Fischer, Mar 02 2021 *)

Crossrefs

Cf. A001354.

Sequence in context: A055536 A131438 A048478 * A294838 A116952 A261478

Adjacent sequences: A001357 A001358 A001359 * A001361 A001362 A001363

Keyword

nonn,easy,nice

Author

N. J. A. Sloane.

Extensions

More terms from Georg Fischer, Mar 02 2021

Status

approved