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

Author

Clark Kimberling

Keywords

• nonn
• easy

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).

Crossrefs

Cf. A000045, A027935.

Programs

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

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

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 *)

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

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

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