OFFSET
0,2
COMMENTS
LINKS
FORMULA
G.f.: (1-2x)/(1-6x+7x^2);
a(n)=((1+sqrt(2))(3+sqrt(2))^n-(1-sqrt(2))(3-sqrt(2))^n)/(sqrt(8)).
PROG
(PARI) a(n)=my(sqrt2=quadgen(8)); simplify(((1+sqrt2)*(3+sqrt2)^n-(1-sqrt2)*(3-sqrt2)^n)/sqrt2^3) \\ Charles R Greathouse IV, Oct 24 2014
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Jul 18 2003
STATUS
approved