A054107 T(n,n-3), array T as in A054106.

1, 3, 8, 15, 27, 44, 67, 97, 135, 182, 239, 307, 387, 480, 587, 709, 847, 1002, 1175, 1367, 1579, 1812, 2067, 2345, 2647, 2974, 3327, 3707, 4115, 4552, 5019, 5517, 6047, 6610, 7207, 7839, 8507, 9212, 9955, 10737, 11559

Offset: 3

Author

Clark Kimberling

Keywords

• nonn
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).

Programs

Mathematica

LinearRecurrence[{4,-6,4,-1},{1,3,8,15,27,44,67},50] (* Harvey P. Dale, Apr 24 2020 *)

Formula

For n>5, a(n) = 1/6 * (n^3 - 6n^2 + 23n - 48).

G.f.: x^3*(1-x+x^2)*(1+x^2-2*x^3+x^4)/(1-x)^4. [Colin Barker, Sep 09 2012]