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a(n) = 5*a(n-2) - 2*a(n-4), n >= 4.
0

%I #15 Mar 12 2024 12:17:40

%S 1,2,5,10,23,46,105,210,479,958,2185,4370,9967,19934,45465,90930,

%T 207391,414782,946025,1892050,4315343,8630686,19684665,39369330,

%U 89792639,179585278,409593865,819187730,1868384047,3736768094,8522732505

%N a(n) = 5*a(n-2) - 2*a(n-4), n >= 4.

%C Floretion Algebra Multiplication Program, FAMP Code: 4kbaseksigcycsumseq[ - .25'i - .25i' + .25'ii' + .25'jj' + .25'kk' + .25'jk' + .25'kj' + .25e], sumtype: (Y[15], *, vesy)

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,5,0,-2).

%F a(2n) = A107839(n), a(2n+1) = A106709(n+1), a(n) - a(n-1) = A005824(n+2).

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

%Y Cf. A107839, A106709, A005824, A054486.

%K easy,nonn

%O 0,2

%A _Creighton Dement_, Aug 18 2005