A110933 Integers k such that 3*10^k + 71 is a prime number.

1, 4, 7, 16, 19, 190, 227, 235, 283, 319, 1655, 3955, 10666, 30724

Offset: 1

Author

Julien Peter Benney (jpbenney(AT)ftml.net), Oct 04 2005

Keywords

• more
• nonn

Comments

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "30071".

a(15) > 10^5. - Robert Price, Jan 22 2017

Examples

			k = 7 is a member because: 3*10^7 + 71 = 30000071, which is prime.
		

Links

• Makoto Kamada, List of near-repdigit-related prime numbers.
• Index entries for primes involving repunits.

Crossrefs

Cf. A049054, A088274, A088275, A095688, A107083, A108049, A108050, A108052, A108054.

Programs

PARI

isok(n) = isprime(3*10^n+71); \\ Michel Marcus, Jan 22 2017

Extensions

a(13) from Ray Chandler, Dec 23 2010

Prepended a(1)=1 by Robert Price, Jan 22 2017

a(14) from Robert Price, Jan 22 2017