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

1,2

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).

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)

Maple

with(combinat); seq(fibonacci(2*n+3) -2*(n+1), n=1..30); # G. C. Greubel, Sep 27 2019

Mathematica

Table[Fibonacci[2*n+3]-2*(n+1), {n, 30}] (* G. C. Greubel, Sep 27 2019 *)

Prog

(Magma) [Fibonacci(2*n+3) - 2*n - 2: n in [1..30]]; // Vincenzo Librandi, Apr 18 2011
(PARI) vector(30, n, fibonacci(2*n+3)-2*(n+1)) \\ G. C. Greubel, Sep 27 2019
(Sage) [fibonacci(2*n+3) -2*(n+1) for n in (1..30)] # G. C. Greubel, Sep 27 2019
(GAP) List([1..30], n-> Fibonacci(2*n+3) -2*(n+1) ); # G. C. Greubel, Sep 27 2019

Crossrefs

Cf. A000045, A027935.

Sequence in context: A183957 A078501 A247557 * A135026 A335639 A027138

Adjacent sequences: A027934 A027935 A027936 * A027938 A027939 A027940

Keyword

nonn,easy

Author

Clark Kimberling

Status

approved