

A165700


Numbers n such that n*10^(n+1)+1 is prime.


0




OFFSET

1,2


COMMENTS

Numbers n such that the number that begins with n, followed by
n zeros, ends with 1 is prime.
Those numbers corresponding to a(4), a(5) and a(6) are probable primes.
There is no further term up to 14000.


LINKS

Table of n, a(n) for n=1..6.


MATHEMATICA

Do[If[PrimeQ[n*10^(n+1)+1], Print[n]], {n, 14000}]


PROG

(PARI) is(n)=isprime(n*10^(n+1)+1) \\ Charles R Greathouse IV, Jun 13 2017


CROSSREFS

Cf. A068817, A084428.
Sequence in context: A207152 A135059 A203200 * A249635 A164135 A119056
Adjacent sequences: A165697 A165698 A165699 * A165701 A165702 A165703


KEYWORD

base,hard,more,nonn


AUTHOR

Farideh Firoozbakht, Sep 25 2009


STATUS

approved



