a(n) is the smallest (n+2)-digit prime consisting of a string of n identical digits d sandwiched between two digits different from d, or -1 if no such prime exists.
A384979
a(n) is the smallest (n+2)-digit prime consisting of a string of n identical digits d sandwiched between two digits different from d, or -1 if no such prime exists.
Terms
- a(0) =11a(1) =101a(2) =1009a(3) =10007a(4) =100003a(5) =1000003a(6) =13333339a(7) =100000007a(8) =1000000007a(9) =13333333339a(10) =100000000003
External references
- oeis: A384979