OFFSET
1,2
FORMULA
Conjecture: a(n) = 2*a(n-1) - a(n-2) + a(n-3) - 2*a(n-4) + a(n-5). G.f. x*(-1-x-x^3-x^2+x^4) / ( (1+x+x^2)*(x-1)^3 ). - R. J. Mathar, Oct 08 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved