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

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

Offset

1,1

Links

Table of n, a(n) for n=1..8.

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 *)

Crossrefs

Cf. A068817 (for values of n).

Sequence in context: A243674 A114758 A088061 * A134069 A137464 A357915

Adjacent sequences: A070217 A070218 A070219 * A070221 A070222 A070223

Keyword

base,nonn

Author

Amarnath Murthy, May 02 2002

Extensions

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

Status

approved