A027938 a(n) = T(2n, n+2), T given by A027935.

1, 16, 92, 365, 1204, 3588, 10093, 27476, 73440, 194345, 511576, 1342936, 3520457, 9222440, 24151764, 63238773, 165571628, 433484476, 1134891605, 2971201740, 7778726776

Offset

2,2

Links

G. C. Greubel, Table of n, a(n) for n = 2..1000

Index entries for linear recurrences with constant coefficients, signature (7,-19,26,-19,7,-1).

Formula

G.f.: x^2*(1+9*x-x^2-x^3) / ((1-x)^4*(1-3*x+x^2)). - Colin Barker, Dec 10 2015

a(n) = Fibonacci(2*n+5) - (4*n^3 + 6*n^2 + 14*n + 15)/3. - G. C. Greubel, Sep 28 2019

Maple

with(combinat); seq(fibonacci(2*n+5) - (4*n^3 +6*n^2 +14*n +15)/3, n=2..30); # G. C. Greubel, Sep 28 2019

Mathematica

Table[Fibonacci[2*n+5] -(4*n^3 +6*n^2 +14*n +15)/3, {n, 2, 30}] (* G. C. Greubel, Sep 28 2019 *)

Prog

(PARI) vector(30, n, my(m=n+1); fibonacci(2*m+5) - (4*m^3 +6*m^2 +14*m +15)/3) \\ G. C. Greubel, Sep 28 2019
(Magma) [Fibonacci(2*n+5) - (4*n^3 +6*n^2 +14*n +15)/3: n in [2..30]]; // G. C. Greubel, Sep 28 2019
(Sage) [fibonacci(2*n+5) - (4*n^3 +6*n^2 +14*n +15)/3 for n in (2..30)] # G. C. Greubel, Sep 28 2019
(GAP) List([2..30], n-> Fibonacci(2*n+5) - (4*n^3 +6*n^2 +14*n +15)/3 ); # G. C. Greubel, Sep 28 2019

Crossrefs

Cf. A000045, A027935.

Sequence in context: A047674 A153029 A170920 * A301527 A185458 A108676

Adjacent sequences: A027935 A027936 A027937 * A027939 A027940 A027941

Keyword

nonn,easy

Author

Clark Kimberling

Status

approved