A155652 9^n-6^n+1.

1, 4, 46, 514, 5266, 51274, 484786, 4503034, 41367106, 377342794, 3426318226, 31018262554, 280252754146, 2528805134314, 22798428290866, 205420947110074, 1850199078944386, 16660255040221834, 149993075340330706

Offset: 0

Author

Mohammad K. Azarian, Jan 31 2009

Keywords

• nonn
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (16,-69,54).

Crossrefs

Cf. A155628, A155629, A155630, A155631, A155632, A155633, A155634, A155635, A155636, A155637, A155638, A155639, A155640, A155641, A155642, A155643, A155644, A155645, A155646, A155647, A155648, A155649, A155650, A155651.

Programs

PARI

a(n)=9^n-6^n+1^n \\ Charles R Greathouse IV, Jun 11 2015

Formula

G.f.: 1/(1-9*x)-1/(1-6*x)+1/(1-x). E.g.f.: e^(9*x)-e^(6*x)+e^x.

a(n)=15*a(n-1)-54*a(n-2)+40 with a(0)=1, a(1)=4 - Vincenzo Librandi, Jul 21 2010