A155198 a(n)=9*a(n-1)+a(n-2), n>2 ; a(0)=1, a(1)=8, a(2)=72 .

1, 8, 72, 656, 5976, 54440, 495936, 4517864, 41156712, 374928272, 3415511160, 31114528712, 283446269568, 2582130954824, 23522624862984, 214285754721680, 1952094417358104, 17783135510944616, 162000314015859648

Offset: 0

Author

Philippe Deléham, Jan 21 2009

Keywords

• nonn
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (9,1).

Programs

Mathematica

LinearRecurrence[{9,1},{1,8,72},20] (* Harvey P. Dale, Aug 22 2016 *)

Formula

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

a(n) = Sum_{k, 0<=k<=n} A155161(n,k)*8^k. - Philippe Deléham, Feb 08 2012