OFFSET
6,2
FORMULA
E.g.f. (1/sqrt(1-x^2))*((x/(1-x))^6)/6!.
a(n)=(n!/6!)*sum(binomial(2*k, k)*binomial(n-2*k-1, 5)/(4^k), k=0..floor((n-6)/2)), n>=6.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Aug 23 2005
STATUS
approved