A134271 - OEIS

%I #13 Oct 31 2019 07:47:18

%S 0,1,2,0,4,4,4,12,12,20,36,44,76,116,164,268,396,596,932,1388,2124,

%T 3252,4900,7500,11404,17300,26404,40108,61004,92916,141220,214924,

%U 327052,497364,756900,1151468,1751628,2665268,4054564,6168524,9385100

%N a(n) = a(n-2) + 2*a(n-3), n > 3; with a(0)=0, a(1)=1, a(2)=2, a(3)=0.

%C Recurrence in A052947.

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (0,1,2).

%F From _R. J. Mathar_, Feb 01 2008: (Start)

%F O.g.f.: 1/2 + (1/2)*(-2*x-5*x^2+1)/(-1+x^2+2*x^3).

%F a(n) = A052947(n-1) + 2*A052947(n-2) - A052947(n-3). (End)

%Y Cf. A078050.

%K nonn,easy

%O 0,3

%A _Paul Curtz_, Jan 30 2008