OFFSET
0,2
FORMULA
PROG
(PARI) {a(n)=local(x=X+X*O(X^n)); polcoeff((1+x^2)/(1-x^2)/(1-2*x-x^2) + x*(3+x^2)/(1-x^4), n, X)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Oct 22 2005
STATUS
approved