

A178429


Numbers n such that 10^n  51 is prime.


2




OFFSET

1,1


LINKS

Table of n, a(n) for n=1..10.
Makoto Kamada, Nearrepdigit numbers of the form AA...AABA.
Makoto Kamada, Prime numbers of the form 99...9949.
Index entries for primes involving repunits.


EXAMPLE

10^4  51 = 9949 which is a prime number.


MAPLE

A178429:=n>`if`(isprime(10^n51), n, NULL): seq(A178429(n), n=1..1000); # Wesley Ivan Hurt, Nov 26 2014


MATHEMATICA

m = 1000; For[n = 1, n < m, If[PrimeQ[10^n  51], Print[n]]; n++ ]


PROG

(PARI) is(n)=ispseudoprime(10^n51) \\ Charles R Greathouse IV, Jun 06 2017


CROSSREFS

Cf. A108330, A108328.
Sequence in context: A052105 A010293 A225987 * A242225 A157818 A048608
Adjacent sequences: A178426 A178427 A178428 * A178430 A178431 A178432


KEYWORD

more,nonn


AUTHOR

Robert Price, Dec 21 2010


EXTENSIONS

a(10) = 50929 found by Robert Price and added by Patrick De Geest, Nov 26 2014


STATUS

approved



