A387251 a(n) = 3^n*n^4.

0, 3, 144, 2187, 20736, 151875, 944784, 5250987, 26873856, 129140163, 590490000, 2593609227, 11019960576, 45535459203, 183742537104, 726413416875, 2821109907456, 10785915553923, 40669853253264, 151467076640907, 557885504160000, 2034339951272643, 7351201499765904, 26345121306126507

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (15,-90,270,-405,243).

Formula

a(n) = 15*a(n-1) - 90*a(n-2) + 270*a(n-3) - 405*a(n-4) + 243*a(n-5).

G.f.: 3*x*(1 + 3*x)*(1 + 30*x + 9*x^2)/(1 - 3*x)^5.

E.g.f.: (27*x^3 + 54*x^2 + 21*x + 1)*(3*x)*exp(3*x).

Mathematica

A387251[n_] := 3^n*n^4; Array[A387251, 25, 0] (* Paolo Xausa, Jan 02 2026 *)

Prog

(PARI) a(n) = 3^n * n^4; \\ Michael B. Porter, Dec 22 2025

Crossrefs

Cf. A000244, A000583, A036290, A062074, A127960.

Sequence in context: A278310 A195936 A323998 * A172145 A100931 A152180

Adjacent sequences: A387248 A387249 A387250 * A387252 A387253 A387254

Keyword

nonn,easy

Author

Enrique Navarrete, Dec 16 2025

Status

approved