A175806 a(n) = 27*2^n.

27, 54, 108, 216, 432, 864, 1728, 3456, 6912, 13824, 27648, 55296, 110592, 221184, 442368, 884736, 1769472, 3538944, 7077888, 14155776, 28311552, 56623104, 113246208, 226492416, 452984832, 905969664, 1811939328, 3623878656, 7247757312, 14495514624, 28991029248

Offset: 0

Author

Vincenzo Librandi, Dec 05 2010

Keywords

• nonn
• easy

Comments

The squares of these terms appear in A159274.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (2).

Crossrefs

Cf. A000079, A159274.

Programs

Magma

[27*2^n: n in [0..40]];

Mathematica

Table[27 2^n, {n, 0, 40}] (* Vincenzo Librandi, Sep 30 2013 *)
NestList[2#&,27,30] (* Harvey P. Dale, Apr 17 2022 *)

PARI

apply(n -> 27*2^n, [0..40]) \\ Satish Bysany, Mar 06 2017

Formula

G.f.: 27/(1-2*x).

From Elmo R. Oliveira, Sep 14 2024: (Start)

E.g.f.: 27*exp(2*x).

a(n) = 27*A000079(n).

a(n) = 2*a(n-1) for n > 0. (End)