A013723 a(n) = 18^(2*n + 1).

18, 5832, 1889568, 612220032, 198359290368, 64268410079232, 20822964865671168, 6746640616477458432, 2185911559738696531968, 708235345355337676357632, 229468251895129407139872768

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 (324).

Crossrefs

Bisection of A001027 (18^n).

Cf. A013708-A013722, A013724-A013729.

Programs

Magma

[18^(2*n+1): n in [0..15]]; // Vincenzo Librandi, Jun 26 2011

Maple

seq(18^(2*n+1),n=0..10); # Nathaniel Johnston, Jun 25 2011

Mathematica

18^(2*Range[0,20]+1) (* or *) NestList[324#&,18,20] (* Harvey P. Dale, Sep 28 2021 *)

PARI

a(n)=18^(2*n+1) \\ Charles R Greathouse IV, Jul 11 2016

Formula

From Philippe Deléham, Nov 28 2008: (Start)

a(n) = 324*a(n-1); a(0)=18.

G.f.: 18/(1-324*x). (End)