OFFSET
0,3
COMMENTS
A transform of A011782 under the mapping g(x)->(1/(1+x^3))g(x/(1+x^3))
LINKS
Index entries for linear recurrences with constant coefficients, signature (2,0,-2,2,0,-1).
FORMULA
G.f.: (1-x+x^3)/((1+x^3)*(1-2*x+x^3)).
a(n) = 2*a(n-1)-2*a(n-3)+2*a(n-4)-a(n-6).
a(n) = sum{k=0..floor(n/3), binomial(n-2*k, k)*(-1)^k*(2^(n-3*k)+0^(n-3*k))/2}.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Oct 20 2004
STATUS
approved