A027114 a(n) = A027113(n, n+2).

3, 9, 20, 40, 77, 145, 270, 500, 923, 1701, 3132, 5764, 10605, 19509, 35886, 66008, 121411, 223313, 410740, 755472, 1389533, 2555753, 4700766, 8646060, 15902587, 29249421, 53798076, 98950092, 181997597, 334745773, 615693470

Offset

2,1

Links

Table of n, a(n) for n=2..32.

Index entries for linear recurrences with constant coefficients, signature (2,0,0,-1).

Formula

G.f.: [3+3x+2x^2]/[(1-x)(1-x-x^2-x^3)].

Mathematica

CoefficientList[Series[(3+3x+2x^2)/((1-x)(1-x-x^2-x^3)), {x, 0, 40}], x] (* or *) LinearRecurrence[{2, 0, 0, -1}, {3, 9, 20, 40}, 40] (* Harvey P. Dale, Sep 26 2017 *)

Crossrefs

Equals A089068(n+2) - 3.

Sequence in context: A293357 A202349 A192951 * A145070 A011796 A164680

Adjacent sequences: A027111 A027112 A027113 * A027115 A027116 A027117

Keyword

nonn

Author

Clark Kimberling

Status

approved