

A104146


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


1



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

1,2


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


LINKS

Table of n, a(n) for n=1..15.


CROSSREFS

a(floor(A030430(n)/10)) = 1.
Sequence in context: A091840 A083985 A109848 * A326405 A193179 A133705
Adjacent sequences: A104143 A104144 A104145 * A104147 A104148 A104149


KEYWORD

nonn,more


AUTHOR

Reinhard Zumkeller, Mar 07 2005


STATUS

approved



