A113436 First row of A113435.

1, 2, 7, 26, 98, 371, 1406, 5329, 20196, 76532, 289997, 1098826, 4163483, 15775426, 59772826, 226477879, 858118966, 3251390237, 12319431012, 46677994276, 176861668393, 670124115506, 2539082288671, 9620514646154, 36451871795186

Offset: 0

Author

Floor van Lamoen, Nov 04 2005

Keywords

• nonn
• easy

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (7,-15,11,-1).

Crossrefs

Cf. A113435.

Programs

Mathematica

CoefficientList[Series[(1 - 5*x + 8*x^2 - 4*x^3)/(1 - 7*x + 15*x^2 - 11*x^3 + x^4), {x,0,50}], x] (* or *) LinearRecurrence[{7,-15,11,-1}, {1, 2,7,26}, 50] (* G. C. Greubel, Mar 10 2017 *)

PARI

my(x='x+ O(x^50)); Vec((1 -5*x +8*x^2 -4*x^3)/(1 -7*x +15*x^2 -11*x^3 +x^4)) \\ G. C. Greubel, Mar 10 2017

Formula

a(n) = A113435(3*n).

a(n) = 7*a(n-1) - 15*a(n-2) + 11*a(n-3) - a(n-4).

G.f.: (1 -5*x +8*x^2 -4*x^3)/(1 -7*x +15*x^2 -11*x^3 +x^4).