A137445 - OEIS

%I #15 Apr 20 2019 08:45:17

%S 3,2,-2,-8,-12,-8,8,32,48,32,-32,-128,-192,-128,128,512,768,512,-512,

%T -2048,-3072,-2048,2048,8192,12288,8192,-8192,-32768,-49152,-32768,

%U 32768,131072,196608,131072,-131072,-524288,-786432,-524288,524288

%N a(n) = 2a(n-1)-2a(n-2), with a(0)=3 and a(1)=2.

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

%F O.g.f.: (3-4x)/(1-2x+2x^2). a(n)=(-1)^(n+1)*A134142(n+1). - _R. J. Mathar_, May 01 2008

%F a(n) = (3/2 - I/2)*(1 - I)^n + (3/2 + I/2)*(1 + I)^n, n>=0. - _Taras Goy_, Apr 20 2019

%t LinearRecurrence[{2,-2},{3,2},40] (* _Harvey P. Dale_, May 03 2018 *)

%K sign

%O 0,1

%A _Paul Curtz_, Apr 18 2008

%E More terms from _R. J. Mathar_, May 01 2008