1*5971e316Smrg[n, a, b] -> { : exists e : 1 <= a <= 7e and 9e <= b <= n } 2*5971e316Smrg 3*5971e316Smrg-1 4*5971e316Smrg 5*5971e316Smrg[n, a, b] -> { [i] : n <= 2i } 6