OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..300
Index entries for linear recurrences with constant coefficients, signature (0,81).
FORMULA
a(n) = (8*9^n + (-9)^n)/9.
G.f.: (1+7*x)/((1+9*x)*(1-9*x)).
E.g.f.: (8*exp(9*x) + exp(-9*x))/9.
a(n) = 81*a(n-2); a(0)=1, a(1)=7. - Harvey P. Dale, May 24 2012
MATHEMATICA
Table[(8*9^n+(-9)^n)/9, {n, 0, 20}] (* or *) LinearRecurrence[{0, 81}, {1, 7}, 20] (* Harvey P. Dale, May 24 2012 *)
PROG
(Magma) [(8*9^n+(-9)^n)/9: n in [0..25]]; // Vincenzo Librandi, Jun 29 2011
(PARI) a(n)=(8*9^n+(-9)^n)/9 \\ Charles R Greathouse IV, Jun 29 2011
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Apr 23 2003
STATUS
approved