OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (-1, 72).
FORMULA
a(n) = 72*a(n-2)-a(n-1), a(0)= 1, a(1)= -8, for n>1.
G.f.: (1-7x)/(1+x-72*x^2).
a(n)= Sum_{k, 0<=k<=n} A112555(n,k)*(-9)^k.
E.g.f.: (1/17)*(exp(8*x) + 16*exp(-9*x)). - G. C. Greubel, May 01 2016
MATHEMATICA
LinearRecurrence[{-1, 72}, {1, -8}, 20] (* Harvey P. Dale, Jun 23 2012 *)
PROG
(PARI) a(n)=(8^n+16*(-9)^n)/17 \\ Charles R Greathouse IV, May 02 2016
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Philippe Deléham, Oct 08 2009
STATUS
approved