A104146 Smallest k>0 such that n*10^k + k is prime.

1, 3, 1, 1, 3, 1, 1, 147, 17, 1, 3, 7, 1, 297, 1

Offset: 1

Author

Reinhard Zumkeller, Mar 07 2005

Keywords

• nonn
• more

Comments

(a(n) mod 10) in {1,3,7,9}.

a(16), if it exists, is greater than 20000. - Ryan Propper, Jul 21 2006

a(16), if it exists, is greater than 42000. - Ryan Propper, Sep 25 2006

Crossrefs

a(floor(A030430(n)/10)) = 1.