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a(n) = 10*a(n-1) - a(n-2).
0

%I #14 Mar 03 2024 14:43:36

%S 1,2,19,188,1861,18422,182359,1805168,17869321,176888042,1751011099,

%T 17333222948,171581218381,1698478960862,16813208390239,

%U 166433604941528,1647522841025041,16308794805308882,161440425212063779,1598095457315328908,15819514147941225301

%N a(n) = 10*a(n-1) - a(n-2).

%C A140780 has the same recursion rule but starts (1, 3, 29,...).

%C a(n)/a(n-1) tends to 2*sqrt(6) + 5 = 9.8989794855...

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (10, -1).

%F a(n) = 10*a(n-1) - a(n-2); n>1; given a(0) = 1, a(1) = 2. a(n) = term (1,1) in X^n, where X = the 2x2 matrix [2,3; 5,8].

%e a(5) = 18422 = 10*a(4) - a(3) = 10*1861 - 188.

%e a(3) = 188 = term (1,1) of X^3.

%t LinearRecurrence[{10, -1}, {1, 2}, 30] (* _Amiram Eldar_, Dec 04 2018 *)

%Y Cf. A140780.

%K nonn

%O 0,2

%A _Gary W. Adamson_, May 30 2008

%E More terms from _Amiram Eldar_, Dec 04 2018