A036949 Smallest n-digit prime containing only the digits 7 and 8, or 0 if no such prime exists.
7, 0, 787, 7877, 78787, 777787, 7778777, 77778887, 777788887, 7777778887, 77777778887, 777777777877, 7777777787777, 77777777778787, 777777777777787, 7777777778788777, 77777777777778887, 777777777787878887
Offset: 1
Links
- Jinyuan Wang, Table of n, a(n) for n = 1..500
Programs
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Mathematica
Table[SelectFirst[FromDigits/@Tuples[{7,8},n],PrimeQ],{n,18}]/.Missing[ "NotFound"]->0 (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Oct 07 2018 *)