A155627 a(n) = 6^n - 4^n + 1.

1, 3, 21, 153, 1041, 6753, 42561, 263553, 1614081, 9815553, 59417601, 358602753, 2160005121, 12993585153, 78095728641, 469111242753, 2816814940161, 16909479575553, 101491237191681, 609084862103553, 3655058928435201

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Index entries for linear recurrences with constant coefficients, signature (11,-34,24).

Formula

O.g.f.: 1/(1 - 6*x) - 1/(1 - 4*x) + 1/(1 - x).

E.g.f.: exp(6*x) - exp(4*x) + exp(x).

a(n) = 10*a(n-1)-24*a(n-2)+15 with a(0)=1, a(1)=3 - Vincenzo Librandi, Jul 21 2010

Prog

(PARI) a(n)=6^n-4^n+1 \\ Charles R Greathouse IV, Jun 11 2015

Crossrefs

Cf. A155596, A155597, A155598, A155599, A155600, A155601, A155622, A155623, A155624, A155625, A155626.

Sequence in context: A074577 A007566 A183412 * A163472 A229809 A074575

Adjacent sequences: A155624 A155625 A155626 * A155628 A155629 A155630

Keyword

nonn,easy

Author

Mohammad K. Azarian, Jan 29 2009

Status

approved