A198645 a(n) = 10*3^n - 1.

9, 29, 89, 269, 809, 2429, 7289, 21869, 65609, 196829, 590489, 1771469, 5314409, 15943229, 47829689, 143489069, 430467209, 1291401629, 3874204889, 11622614669, 34867844009, 104603532029, 313810596089, 941431788269, 2824295364809

Offset: 0

Author

Vincenzo Librandi, Oct 28 2011

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (4,-3).

Crossrefs

Cf. A048473.

Programs

Magma

[10*3^n-1: n in [0..30]]

Mathematica

10 * 3^Range[0,30]-1 (* Harvey P. Dale, Feb 28 2022 *)

Formula

a(n) = 3*a(n-1) + 2, a(0)=9.

G.f. ( 9-7*x ) / ( (3*x-1)*(x-1) ). - R. J. Mathar, Oct 30 2011