OFFSET
0,2
LINKS
FORMULA
G.f.: (1-15*x)/(1 - 20*x + 50*x^2);
a(n) = (10 + 5*sqrt(2))^n*(1/2 - sqrt(2)/4) + (10 - 5*sqrt(2))^n*(1/2 + sqrt(2)/4).
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Mar 26 2004
STATUS
approved