A178531 Numbers n such that 10^n - 93 is prime.

2, 3, 4, 5, 6, 7, 11, 57, 61, 70, 127, 223, 237, 240, 310, 467, 651, 1935, 2333, 3457, 4456, 6048, 11289, 12150, 24693, 28437, 31123, 32909, 52041, 58225, 68297, 201801

Offset: 1

Author

Robert Price, Dec 23 2010

Keywords

• more
• nonn

Comments

a(33) > 3*10^5.

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "99907" or "9w07".

Examples

			10^3 - 93 = 907 which is a prime number.
		

Links

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

Crossrefs

Cf. A108330, A108328.

Programs

Mathematica

m=1000; For[n=1, n
				

PARI

is(n)=ispseudoprime(10^n-93) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(29-31) from Robert Price, May 29 2011

a(32) from Robert Price, Jun 21 2023