




OFFSET

1,1


COMMENTS

Except for the first term, each term must both begin and end with a "1" because each term greater than 2 must end in a "1" and if a term begins with a "2" the sum of the digits of the term will be divisible by 3 and thus the term is not a prime.  Harvey P. Dale, Jun 22 2019
The next term (a(5)) has 139 digits and a(6) has 627 digits.  Harvey P. Dale, Jun 22 2019


LINKS



MATHEMATICA

Join[{2}, Select[Table[FromDigits[PadRight[{}, 2n+1, {1, 2}]], {n, 30}], PrimeQ]] (* Harvey P. Dale, Jun 22 2019 *)


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



