OFFSET
1,2
LINKS
FORMULA
a(n) = 8*a(n-1) + a(n-2) - 8*a(n-3).
G.f.: x*(1+2*x)/((1-8*x)*(1-x^2)). a(n) = (20*8^n+7*(-1)^n-27)/126. - Bruno Berselli, Jan 20 2011
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
STATUS
approved