A108052 Integers n such that 10^n+19 is a prime number.

1, 3, 5, 7, 10, 11, 17, 59, 81, 108, 574, 629, 1069, 1759, 2063, 2682, 9174, 40929, 42457, 66033

Offset

1,2

Comments

Verified terms through 9174. - Robert Price, May 24 2010

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "10019".

No other terms <= 100,000. - Robert Price, Mar 03 2011

Links

Table of n, a(n) for n=1..20.

Makoto Kamada, List of near-repdigit-related prime numbers.

Index entries for primes involving repunits.

Example

n = 7 we have 10^7+19 = 10000000+19 = 10000019, which is prime.

Mathematica

Select[Range[2*10^3], PrimeQ[10^#+19]&] - Vladimir Joseph Stephan Orlovsky, Apr 29 2008

Prog

(PARI) is(n)=ispseudoprime(10^n+19) \\ Charles R Greathouse IV, Apr 28 2015

Crossrefs

Cf. A049054, A088274, A088275, A095688.

Sequence in context: A350575 A206812 A189372 * A359113 A046868 A225240

Adjacent sequences: A108049 A108050 A108051 * A108053 A108054 A108055

Keyword

more,nonn

Author

Julien Peter Benney (jpbenney(AT)ftml.net), Jun 01 2005

Extensions

a(17)=9174 from Ryan Propper, Jan 02 2008

Edited by Ray Chandler, Dec 23 2010

a(18)=40929 and a(19)=42457 from Robert Price, Dec 27 2010

a(20)=66033 from Robert Price, Jan 09 2011

Status

approved