A104760 Smallest semiprime containing exactly n 7's.

57, 77, 3777, 17777, 277777, 1777777, 17777777, 707777777, 3777777777, 17777777777, 577777777777, 1777777777777, 37777777777777, 757777777777777, 4777777777777777, 37777777777777777, 277777777777777777

Offset: 1

Author

Shyam Sunder Gupta, Apr 24 2005

Keywords

• base
• nonn

Examples

			a(2)=77 because 77 is the smallest semiprime containing exactly two 7's.