A199566 (7*9^n+1)/2.

4, 32, 284, 2552, 22964, 206672, 1860044, 16740392, 150663524, 1355971712, 12203745404, 109833708632, 988503377684, 8896530399152, 80068773592364, 720618962331272, 6485570660981444, 58370135948832992, 525331223539496924

Offset

0,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (10,-9).

Formula

a(n) = 4*A187709(n).

a(n) = 9*a(n-1)-4.

a(n) = 10*a(n-1)-9*a(n-2).

G.f.: 4*(1-2*x)/((1-x)*(1-9*x)).

Mathematica

(7*9^Range[0, 20]+1)/2 (* or *) LinearRecurrence[{10, -9}, {4, 32}, 20] (* Harvey P. Dale, Dec 08 2012 *)

Prog

(Magma) [(7*9^n+1)/2: n in [0..30]];

Crossrefs

Sequence in context: A145710 A264633 A319183 * A370160 A366663 A110901

Adjacent sequences: A199563 A199564 A199565 * A199567 A199568 A199569

Keyword

nonn,easy

Author

Vincenzo Librandi, Nov 08 2011

Status

approved