93860domain: NAppears in sequencesa(n) = n^2*(n+1)*(2*n+1)/3.at n=18A098077Numbers k such that k and k^2 use only the digits 0, 3, 6, 8 and 9.at n=49A136945Number of (w,x,y,z) with all terms in {1,...,n} and w>2x and y>3z.at n=40A212518