A113437 Second row of A113435.

1, 3, 11, 41, 154, 581, 2197, 8317, 31501, 119338, 452141, 1713111, 6490879, 24593701, 93184802, 353074657, 1337790401, 5068852073, 19205744921, 72770053106, 275723780329, 1044710007771, 3958378188707, 14998188734897

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 - 4*x + 5*x^2 - 2*x^3)/(1 - 7*x + 15*x^2 - 11*x^3 + x^4), {x,0,50}], x] (* G. C. Greubel, Mar 11 2017 *)
LinearRecurrence[{7,-15,11,-1},{1,3,11,41},30] (* Harvey P. Dale, May 09 2018 *)

PARI

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

Formula

a(n) = A113435(3*n+1).

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

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