A013714 a(n) = 9^(2*n + 1).

9, 729, 59049, 4782969, 387420489, 31381059609, 2541865828329, 205891132094649, 16677181699666569, 1350851717672992089, 109418989131512359209, 8862938119652501095929, 717897987691852588770249, 58149737003040059690390169, 4710128697246244834921603689

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..150
• Tanya Khovanova, Recursive Sequences
• Index entries for linear recurrences with constant coefficients, signature (81).

Crossrefs

Cf. A001019, A005408, A013778.

Programs

Magma

[9^(2*n+1): n in [0..20]]; // Vincenzo Librandi, May 26 2011

Mathematica

9^(2*Range[0,20]+1) (* or *) NestList[81#&,9,20] (* Harvey P. Dale, May 25 2020 *)

PARI

a(n)=9^(2*n+1) \\ Charles R Greathouse IV, Jul 11 2016

Formula

From Philippe Deléham, Nov 25 2008: (Start)

a(n) = 81*a(n-1); a(0)=9.

G.f.: 9/(1-81*x). (End)

From Elmo R. Oliveira, Aug 26 2024: (Start)

E.g.f.: 9*exp(81*x).

a(n) = 3*A013778(n) = A001019(A005408(n)). (End)