a(n) is the smallest 2*n + 1 digit prime consisting of a string of 2*n - 1 identical digits d sandwiched between two same digits different from d, or -1 if no such prime exists.
A385144
a(n) is the smallest 2*n + 1 digit prime consisting of a string of 2*n - 1 identical digits d sandwiched between two same digits different from d, or -1 if no such prime exists.
Terms
- a(0) =101a(1) =13331a(2) =1333331a(3) =188888881a(4) =74444444447a(11) =-1a(12) =-1
External references
- oeis: A385144