OFFSET
0,2
REFERENCES
I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, Wiley, N.Y., 1983, (Example 2.8.11).
FORMULA
G.f.: (1+x^5+x^6+x^7-x^9)/(1+x^5-x^6-x^9-2*x-x^8+x^10). a(n) = 2*a(n-1)-a(n-5)+a(n-6)+a(n-8)+a(n-9)-a(n-10).
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladeta Jovovic, Jun 14 2001
STATUS
approved