A198851 a(n) = 3*8^n-1.

2, 23, 191, 1535, 12287, 98303, 786431, 6291455, 50331647, 402653183, 3221225471, 25769803775, 206158430207, 1649267441663, 13194139533311, 105553116266495, 844424930131967, 6755399441055743, 54043195528445951

Offset

0,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (9,-8).

Formula

a(n) = 8*a(n-1)+7. a(n) = 9*a(n-1)-8*a(n-2) for n > 1.

G.f.: (5*x+2)/(8*x^2-9*x+1) [Harvey P. Dale, Dec 07 2011]

Mathematica

3*8^Range[0, 30]-1 (* or *) LinearRecurrence[{9, -8}, {2, 23}, 30] (* Harvey P. Dale, Dec 07 2011 *)

Prog

(Magma) [3*8^n-1: n in [0..30]]

Crossrefs

Sequence in context: A130547 A352355 A200846 * A173341 A118756 A133955

Adjacent sequences: A198848 A198849 A198850 * A198852 A198853 A198854

Keyword

nonn,easy

Author

Vincenzo Librandi, Oct 31 2011

Status

approved