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

0,2

Links

Paolo Xausa, Table of n, a(n) for n = 0..500

Index entries for linear recurrences with constant coefficients, signature (18,-9)

Formula

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

Mathematica

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

Crossrefs

Sequence in context: A274502 A249642 A093849 * A246641 A169958 A012017

Adjacent sequences: A165229 A165230 A165231 * A165233 A165234 A165235

Keyword

nonn,easy

Author

Philippe Deléham, Sep 09 2009

Status

approved