A054121 T(n,n-3), array T as in A054120.

1, 9, 39, 114, 261, 507, 879, 1404, 2109, 3021, 4167, 5574, 7269, 9279, 11631, 14352, 17469, 21009, 24999, 29466, 34437, 39939, 45999, 52644, 59901, 67797, 76359, 85614, 95589, 106311, 117807, 130104, 143229, 157209

Offset

3,2

Links

Table of n, a(n) for n=3..36.

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

Formula

For n>3, a(n) = 3/2 * (3n^3-30n^2+107n-134).

Mathematica

LinearRecurrence[{4, -6, 4, -1}, {1, 9, 39, 114, 261}, 40] (* Harvey P. Dale, Sep 28 2017 *)

Prog

(PARI) a(n)=max(9*n^3-90*n^2+321*n-402, 2)/2  \\ Charles R Greathouse IV, Oct 19 2022

Crossrefs

Sequence in context: A226449 A299280 A023163 * A139594 A034263 A060929

Adjacent sequences: A054118 A054119 A054120 * A054122 A054123 A054124

Keyword

nonn,easy

Author

Clark Kimberling

Status

approved