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a(n) = 2^n - 9.
9

%I #28 Nov 08 2023 06:35:40

%S -8,-7,-5,-1,7,23,55,119,247,503,1015,2039,4087,8183,16375,32759,

%T 65527,131063,262135,524279,1048567,2097143,4194295,8388599,16777207,

%U 33554423,67108855,134217719,268435447,536870903,1073741815,2147483639,4294967287,8589934583

%N a(n) = 2^n - 9.

%H G. C. Greubel, <a href="/A185346/b185346.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 (3,-2).

%F G.f.: ( -8+17*x ) / ( (2*x-1)*(x-1) ). - _R. J. Mathar_, Dec 17 2012

%F E.g.f.: exp(2*x) - 9*exp(x). - _G. C. Greubel_, Jun 28 2017

%F From _Elmo R. Oliveira_, Nov 08 2023: (Start)

%F a(n) = 2*a(n-1) + 9 with a(0) = -8.

%F a(n) = 3*a(n-1) - 2*a(n-2) for n > 1. (End)

%p A185346:=n->2^n-9: seq(A185346(n), n=0..50); # _Wesley Ivan Hurt_, Jun 28 2017

%t Table[2^n - 9, {n, 0, 40}] (* _T. D. Noe_, Dec 04 2012 *)

%o (PARI) a(n)=2^n-9 \\ _Charles R Greathouse IV_, Oct 07 2015

%Y Cf. A000225, A036563, A172252 (essentially the same).

%K sign,easy

%O 0,1

%A _Andreas Rieber_, Dec 04 2012