A114909 a(n) is the largest base-7 string such that the n-th number coprime to 7 does not divide any substring of a(n).

5, 55, 656, 6662, 55555, 6565321, 66566566, 666566633, 6666612543, 65656565656, 666666666513, 66656665654315, 656565653543211, 6666666666666212, 66566566566566566, 665665665623461651

Offset: 2

Author

Don Reble, Feb 20 2006

Keywords

• nonn
• base

Examples

			a(3) = 55 (base 7) because the 3rd number coprime to 7 is 3, and 3 does not divide any substring of a(3).