A108152 a(n)= 3*a(n-1) +2*a(n-2) +a(n-3).

1, 0, 2, 7, 25, 91, 330, 1197, 4342, 15750, 57131, 207235, 751717, 2726752, 9890925, 35877996, 130142590, 472074687, 1712387237, 6211453675, 22531210186, 81728925145, 296460649482, 1075371008922, 3900763250875, 14149492419951

Offset: 0

Author

Roger L. Bagula, Jun 06 2005

Keywords

• nonn
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (3,2,1).

Crossrefs

Cf. A000073, A001590.

Programs

Mathematica

M = {{0, 1, 0}, {0, 0, 1}, {1, 2, 3}} a3 = Table[MatrixPower[M, i][[1, 2]], {i, 1, 50}]
LinearRecurrence[{3,2,1},{1,0,2},30] (* Harvey P. Dale, Jun 06 2016 *)

Formula

G.f.: (-1+3*x)/(-1+3*x+2*x^2+x^3). [Sep 28 2009]

a(n) = A108153(n+1) -3*A108153(n). [Sep 28 2009]

Extensions

Definition replaced by recurrence by the Associate Editors of the OEIS, Sep 28 2009