

A178434


Numbers n such that 10^n  71 is prime.


0



2, 3, 4, 5, 7, 9, 10, 14, 22, 98, 127, 151, 158, 274, 377, 1015, 2146, 8499, 13885, 13991, 17834, 18211, 36271, 52317, 53804, 104212, 117059, 178695
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OFFSET

1,1


COMMENTS

a(29) > 2.5*10^5.  Robert Price, Apr 12 2015


LINKS

Table of n, a(n) for n=1..28.
Makoto Kamada, Nearrepdigit numbers of the form AA...AABA.
Makoto Kamada, Prime numbers of the form 99...9929.
Index entries for primes involving repunits.


EXAMPLE

10^4  71 = 9929 which is a prime number.


MATHEMATICA

nMax=1000; Do[If[PrimeQ[10^n71], Print[n]], {n, nMax}]


PROG

(PARI) is(n)=ispseudoprime(10^n71) \\ Charles R Greathouse IV, Jun 13 2017


CROSSREFS

Cf. A108330, A108328.
Sequence in context: A274583 A055600 A139528 * A267439 A262691 A117290
Adjacent sequences: A178431 A178432 A178433 * A178435 A178436 A178437


KEYWORD

more,nonn,changed


AUTHOR

Robert Price, Dec 21 2010


EXTENSIONS

a(24:25)=52317,53804 from Robert Price, Apr 25 2011
a(26)a(28) from Kamada data by Robert Price, Apr 12 2015


STATUS

approved



