OFFSET
0,2
FORMULA
G.f.: (1+x-x^2)/(1-4*x+2*x^2-5*x^3+x^4).
PROG
(PARI) a(n)=sum(k=0, n, polcoeff((2+3*z+z^2+z*O(z^k))^(n-k\2), k, z))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Oct 20 2004
EXTENSIONS
Corrected by T. D. Noe, Oct 25 2006
STATUS
approved