A113628 Primes of the form 10 followed by a string of 1's.

101, 10111, 101111, 101111111, 101111111111, 101111111111111111, 10111111111111111111111111111111111111111111111111111111111111111111

Offset

1,1

Comments

a(7)=10b, where b is the repunit with 66 digits (shown here), but a(8)=10c, where c is the repunit with 138 digits and is too large to include. - Stefan Steinerberger, Nov 12 2005

Links

Table of n, a(n) for n=1..7.

Mathematica

Select[Table[FromDigits[PadRight[{1, 0}, n, 1]], {n, 70}], PrimeQ] (* Harvey P. Dale, Oct 04 2015 *)

Crossrefs

Sequence in context: A261965 A255892 A065074 * A135375 A267622 A172162

Adjacent sequences: A113625 A113626 A113627 * A113629 A113630 A113631

Keyword

base,nonn

Author

Amarnath Murthy, Nov 10 2005

Extensions

More terms from Stefan Steinerberger, Nov 12 2005

Status

approved