A155645 7^n+6^n-1.

1, 12, 84, 558, 3696, 24582, 164304, 1103478, 7444416, 50431302, 342941424, 2340123798, 16018069536, 109949704422, 756587236944, 5217746494518, 36054040477056, 249557173431942, 1729973554578864, 12008254925383638

Offset

0,2

Links

Table of n, a(n) for n=0..19.

Index entries for linear recurrences with constant coefficients, signature (14,-55,42).

Formula

G.f.: 1/(1-7*x)+1/(1-6*x)-1/(1-x). E.g.f.: e^(7*x)+e^(6*x)-e^x.

a(n)=13*a(n-1)-42*a(n-2)-30 with a(0)=1, a(1)=12 - Vincenzo Librandi, Jul 21 2010

a(0)=1, a(1)=12, a(2)=84, a(n)=14*a(n-1)-55*a(n-2)+42*a(n-3) [From Harvey P. Dale, May 08 2012]

Mathematica

Table[7^n+6^n-1, {n, 0, 20}] (* or *) LinearRecurrence[{14, -55, 42}, {1, 12, 84}, 20] (* Harvey P. Dale, May 08 2012 *)

Prog

(PARI) a(n)=7^n+6^n-1 \\ Charles R Greathouse IV, Jun 11 2015

Crossrefs

Cf. A155628, A155629, A155630, A155631, A155632, A155633, A155634, A155635, A155636, A155637, A155638, A155639, A155640, A155641, A155642, A155643, A155644.

Sequence in context: A000761 A174079 A003209 * A336907 A095267 A118017

Adjacent sequences: A155642 A155643 A155644 * A155646 A155647 A155648

Keyword

nonn,easy

Author

Mohammad K. Azarian, Jan 31 2009

Status

approved