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a(n) = 10*a(n-2) - 16*a(n-4) for n > 3, a(0) = 1, a(1) = 5, a(2) = 14, a(3) = 34.
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%I #15 Nov 12 2018 07:39:54

%S 1,5,14,34,124,260,1016,2056,8176,16400,65504,131104,524224,1048640,

%T 4194176,8388736,33554176,67109120,268434944,536871424,2147482624,

%U 4294968320,17179867136,34359740416,137438949376,274877911040

%N a(n) = 10*a(n-2) - 16*a(n-4) for n > 3, a(0) = 1, a(1) = 5, a(2) = 14, a(3) = 34.

%C a(n)/A083333(n) converges to 3.

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0, 10, 0, -16).

%F G.f.: (1 + 5*x + 4*x^2 - 16*x^3)/(1 - 10*x^2 + 16*x^4).

%F a(n) = A016116(n)*A014551(n+1). - _R. J. Mathar_, Jul 08 2009

%F From _Franck Maminirina Ramaharo_, Nov 12 2018: (Start)

%F a(n) = sqrt(2)^(3*n - 1)*(1 + sqrt(2) + (-1)^n*(sqrt(2) - 1)) + sqrt(2)^(n - 3)*(1 - sqrt(2) - (-1)^n*(sqrt(2) + 1)).

%F E.g.f.: (sinh(sqrt(2)*x) + 2*sinh(2*sqrt(2)*x))/sqrt(2) - cosh(sqrt(2)*x) + 2*cosh(2*sqrt(2)*x). (End)

%t CoefficientList[Series[(1+5x+4x^2-16x^3)/(1-10x^2+16x^4), {x, 0, 30}], x]

%o (Maxima) (a[0] : 1, a[1] : 5, a[2] : 14, a[3] : 34, a[n] := 10*a[n - 2] - 16*a[n - 4], makelist(a[n], n, 0, 50));/* _Franck Maminirina Ramaharo_, Nov 12 2018 */

%Y Cf. A147590, A081342 (bisections). [_R. J. Mathar_, Jul 13 2009]

%Y Cf. A199710. [_Bruno Berselli_, Nov 11 2011]

%K nonn,easy

%O 0,2

%A Mario Catalani (mario.catalani(AT)unito.it), Apr 24 2003