OFFSET
0,2
FORMULA
For n >= 9, a(n) = 3*a(n-1)-a(n-2)-5*a(n-3)+5*a(n-4)+a(n-5)-3*a(n-6)+a(n-7).
O.g.f.: (x^7-x^6+3x^5+7x^4+22x^3+7x^2+1)/((1+x)^2*(x-1)^4) . - R. J. Mathar, May 28 2008
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved