Largest n-digit squarefree number.

Terms

a(0) =7a(1) =97a(2) =998a(3) =9998a(4) =99998a(5) =999997a(6) =9999998a(7) =99999998a(8) =999999998a(9) =9999999998a(10) =99999999998a(11) =999999999998