A036938 Smallest n-digit prime containing only digits 2 and 7, or 0 if no such prime exists.
2, 0, 227, 2777, 22277, 272227, 2227727, 22227277, 222222227, 2222222777, 22222222277, 222222272777, 2222222227727, 22222222777277, 222222222222227, 2222222222227727, 22222222222227227, 222222222227227727
Offset: 1
Links
- Jinyuan Wang, Table of n, a(n) for n = 1..500