999990domain: NAppears in sequencesa(n) is the least positive integer in base 10 containing n nines that is divisible by n.at n=4A112909a(n) = 10*(10^n-1).at n=5A124167a(n) = n^6 - n.at n=10A131473Numbers m such that the largest digit in the decimal expansion of 1/m is 1.at n=38A333402