A027937 a(n) = T(2*n, n+1), T given by A027935.
1, 7, 26, 79, 221, 596, 1581, 4163, 10926, 28635, 75001, 196392, 514201, 1346239, 3524546, 9227431, 24157781, 63245948, 165580101, 433494395, 1134903126, 2971215027, 7778742001, 20365011024, 53316291121
Offset: 1
Links
- G. C. Greubel, Table of n, a(n) for n = 1..1000
- Index entries for linear recurrences with constant coefficients, signature (5,-8,5,-1).
Programs
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GAP
List([1..30], n-> Fibonacci(2*n+3) -2*(n+1) ); # G. C. Greubel, Sep 27 2019
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Magma
[Fibonacci(2*n+3) - 2*n - 2: n in [1..30]]; // Vincenzo Librandi, Apr 18 2011
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Maple
with(combinat); seq(fibonacci(2*n+3) -2*(n+1), n=1..30); # G. C. Greubel, Sep 27 2019
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Mathematica
Table[Fibonacci[2*n+3]-2*(n+1), {n,30}] (* G. C. Greubel, Sep 27 2019 *) -
PARI
vector(30, n, fibonacci(2*n+3)-2*(n+1)) \\ G. C. Greubel, Sep 27 2019
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Sage
[fibonacci(2*n+3) -2*(n+1) for n in (1..30)] # G. C. Greubel, Sep 27 2019
Formula
a(n) = Fibonacci(2*n+3) - 2*n - 2.
From R. J. Mathar, Feb 06 2010: (Start)
a(n) = 5*a(n-1) - 8*a(n-2) + 5*a(n-3) - a(n-4);
G.f.: x*(1 + 2*x - x^2)/((1-3*x+x^2)*(1-x)^2). (End)