33059881728domain: NAppears in sequencesNumbers k such that d(k)^4 divides k.at n=18A046756a(n) = 3*a(n-1) if n is odd, otherwise 6*a(n-1).at n=17A130505Expansion of (1-3*x)/(1-6*x+18*x^2).at n=17A193410