%I #22 Mar 08 2024 11:57:58

%S 5,21,95,433,1975,9009,41095,187457,855095,3900561,17792615,81161953,

%T 370224535,1688798769,7703544775,35140126337,160293542135,

%U 731187458001,3335350205735,15214376112673,69401180151895,316577148534129

%N a(n+1) = 5*a(n) - 2*a(n-1).

%H G. C. Greubel, <a href="/A159289/b159289.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (5, -2).

%F From _R. J. Mathar_, Apr 10 2009: (Start)

%F G.f.: -(-5+4*x)/(1-5*x+2*x^2).

%F a(n) = 5*A107839(n) - 4*A107839(n-1). (End)

%t LinearRecurrence[{5, -2}, {5, 21}, 50] (* _G. C. Greubel_, Jun 27 2018 *)

%o (PARI) x='x+O('x^30); Vec(-(-5+4*x)/(1-5*x+2*x^2)) \\ _G. C. Greubel_, Jun 27 2018

%o (Magma) I:=[5, 21]; [n le 2 select I[n] else 5*Self(n-1) - 2*Self(n-2): n in [1..30]]; // _G. C. Greubel_, Jun 27 2018

%Y Cf. A107839.

%K nonn,easy

%O 0,1

%A _Creighton Dement_, Apr 08 2009