A070220 Primes of the form n (written in base 10) followed by n 1's.

11, 211, 511111, 71111111, 101111111111, 161111111111111111, 2011111111111111111111, 6511111111111111111111111111111111111111111111111111111111111111111

Offset: 1

Author

Amarnath Murthy, May 02 2002

Keywords

• base
• nonn

Crossrefs

Cf. A068817 (for values of n).

Programs

Mathematica

Do[p = FromDigits[ Join[ IntegerDigits[n], IntegerDigits[(10^n - 1)/9]]]; If[ PrimeQ[p], Print[p]], {n, 1, 100}]
Select[Table[FromDigits[Join[IntegerDigits[n],PadRight[{},n,1]]],{n,100}],PrimeQ] (* Harvey P. Dale, Jun 08 2021 *)

Extensions

More terms from Vladeta Jovovic and Robert G. Wilson v, May 03 2002