A382677 a(n) = 9 - 28 * 2^n + 20 * 3^n.

1, 13, 77, 325, 1181, 3973, 12797, 40165, 124061, 379333, 1152317, 3485605, 10514141, 31657093, 95200637, 286060645, 859099421, 2579133253, 7741069757, 23230549285, 69706327901, 209148343813, 627503751677, 1882628695525, 5648120967581, 16944832664773

Offset

0,2

Links

Paolo Xausa, Table of n, a(n) for n = 0..2000

Index entries for linear recurrences with constant coefficients, signature (6,-11,6).

Formula

From Stefano Spezia, Aug 30 2025: (Start)

G.f.: (1 + 2*x)*(1 + 5*x)/((1 - x)*(1 - 2*x)*(1 - 3*x)).

E.g.f.: exp(x)*(2*exp(x) - 1)*(10*exp(x) - 9). (End)

Mathematica

A382677[n_] := 20*3^n - 28*2^n + 9; Array[A382677, 30, 0] (* or *)
LinearRecurrence[{6, -11, 6}, {1, 13, 77}, 30] (* Paolo Xausa, Jan 08 2026 *)

Prog

(PARI) a(n) = 9-28*2^n+20*3^n;

Crossrefs

Column k=2 of A382674.

Row n=2 of A382674.

Sequence in context: A044581 A126423 A072474 * A186103 A194713 A047638

Adjacent sequences: A382674 A382675 A382676 * A382678 A382679 A382680

Keyword

nonn,easy

Author

Seiichi Manyama, Apr 03 2025

Status

approved