A155656 9^n+7^n-1.

1, 15, 129, 1071, 8961, 75855, 649089, 5606511, 48811521, 427774095, 3769259649, 33358386351, 296270823681, 2638754838735, 23555015527809, 210638693604591, 1886253119421441, 16909812213653775, 151723048894909569

Offset

0,2

Links

Table of n, a(n) for n=0..18.

Index entries for linear recurrences with constant coefficients, signature (17,-79,63).

Formula

G.f.: 1/(1-9*x)+1/(1-7*x)-1/(1-x). E.g.f.: e^(9*x)+e^(7*x)-e^x.

a(n)=16*a(n-1)-63*a(n-2)-48 with a(0)=1, a(1)=15 - Vincenzo Librandi, Jul 21 2010

Prog

(PARI) a(n)=9^n+7^n-1 \\ Charles R Greathouse IV, Jun 11 2015

Crossrefs

Cf. A155638, A155639, A155640, A155641, A155642, A155643, A155644, A155645, A155646, A155647, A155648, A155649, A155650, A155651, A155652, A155653, A155654, A155655.

Sequence in context: A294054 A156922 A271791 * A244878 A275101 A236262

Adjacent sequences: A155653 A155654 A155655 * A155657 A155658 A155659

Keyword

nonn,easy

Author

Mohammad K. Azarian, Jan 31 2009

Status

approved