A165232 a(0)=1, a(1)=9, a(n) = 18*a(n-1) - 9*a(n-2) for n>1.

1, 9, 153, 2673, 46737, 817209, 14289129, 249849441, 4368687777, 76387735017, 1335661040313, 23354409110481, 408358414625841, 7140261781270809, 124849486331241993

Offset: 0

Author

Philippe Deléham, Sep 09 2009

Keywords

• nonn
• easy

Links

• Paolo Xausa, Table of n, a(n) for n = 0..500
• Index entries for linear recurrences with constant coefficients, signature (18,-9)

Programs

Mathematica

LinearRecurrence[{18,-9},{1,9},25] (* Paolo Xausa, Jan 04 2024 *)

Formula

G.f.: (1-9*x)/(1-18*x+9*x^2).