A128782 a(n) = n^2*4^n.

0, 4, 64, 576, 4096, 25600, 147456, 802816, 4194304, 21233664, 104857600, 507510784, 2415919104, 11341398016, 52613349376, 241591910400, 1099511627776, 4964982194176, 22265110462464, 99230924406784, 439804651110400, 1939538511396864, 8514618045497344, 37225065669984256

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (12,-48,64).

Formula

From R. J. Mathar, Sep 20 2011: (Start)

G.f.: 4*x*(1 + 4*x)/(1 - 4*x)^3 .

a(n) = 4*A086952(n). (End)

E.g.f.: 4*exp(4*x)*x*(1 + 4*x). - Stefano Spezia, Oct 09 2022

Mathematica

Table[n^2 * 4^n, {n, 0, 30}] (* Vincenzo Librandi, Feb 06 2013 *)

Prog

(Magma) [n^2*4^n: n in [0..20]]; // Vincenzo Librandi, Feb 06 2013

Crossrefs

Cf. A036289, A007758, A086952.

Sequence in context: A343725 A195800 A224446 * A353453 A318779 A264567

Adjacent sequences: A128779 A128780 A128781 * A128783 A128784 A128785

Keyword

nonn,easy

Author

Mohammad K. Azarian, Apr 07 2007

Status

approved