A001360 - OEIS

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

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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