A013732 a(n) = 3^(3*n + 1).

3, 81, 2187, 59049, 1594323, 43046721, 1162261467, 31381059609, 847288609443, 22876792454961, 617673396283947, 16677181699666569, 450283905890997363, 12157665459056928801, 328256967394537077627, 8862938119652501095929

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200
• Tanya Khovanova, Recursive Sequences
• Index entries for linear recurrences with constant coefficients, signature (27).

Crossrefs

Cf. A013730, A013733, A013734.

Programs

Magma

[3^(3*n+1): n in [0..25]]; // Vincenzo Librandi, May 25 2011

Maple

seq(3^(3*n+1),n=0..15); # Nathaniel Johnston, Jun 26 2011

Mathematica

NestList[27#&,3,20] (* Harvey P. Dale, Apr 01 2018 *)

PARI

a(n)=3^(3*n+1) \\ Charles R Greathouse IV, Jul 11 2016

Formula

From Philippe Deléham, Nov 25 2008: (Start)

a(n) = 27*a(n-1); a(0)=3.

G.f.: 3/(1-27*x). (End)