A102485 a(n) = 5*3^n - 4*2^n.

1, 7, 29, 103, 341, 1087, 3389, 10423, 31781, 96367, 291149, 877543, 2640821, 7938847, 23849309, 71613463, 214971461, 645176527, 1936053869, 5809210183, 17429727701, 52293377407, 156888520829, 470682339703, 1412080573541, 4236308829487, 12709060706189

Offset

0,2

References

B. M. E. Moret and H. D. Shapiro, Algorithms from P to NP, Benjamin/Cummings, Vol. 1, 1991; p. 63.

Links

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

Index entries for linear recurrences with constant coefficients, signature (5,-6).

Formula

a(n) = 5*a(n - 1) - 6*a(n - 2).

G.f.: (1+2*x)/((1-2*x)*(1-3*x)). - Colin Barker, Jan 14 2012

a(n) = A217764(n,8). - Ross La Haye, Mar 27 2013

Maple

a := proc(n) option remember; if n = 0 then RETURN(1) end if; if n = 1 then RETURN(7) end if; 5*a(n - 1) - 6*a(n - 2); end proc;

Mathematica

LinearRecurrence[{5, -6}, {1, 7}, 30] (* Vincenzo Librandi, Jan 15 2012 *)

Prog

(Magma) I:=[1, 7]; [n le 2 select I[n] else 5*Self(n-1)-6*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Jan 15 2012
(PARI) a(n)=5*3^n-4<<n \\ Charles R Greathouse IV, Jan 15 2012

Crossrefs

Sequence in context: A193655 A369805 A227086 * A246038 A049349 A124828

Adjacent sequences: A102482 A102483 A102484 * A102486 A102487 A102488

Keyword

nonn,easy

Author

N. J. A. Sloane, Feb 25 2005

Extensions

New definition from Ralf Stephan, May 17 2007

Status

approved