A178430 Numbers n such that 10^n - 53 is prime.

2, 3, 11, 15, 23, 29, 44, 71, 83, 95, 159, 383, 404, 548, 633, 6409, 8793, 24146, 25727, 64436, 74335, 76875

Offset: 1

Author

Robert Price, Dec 21 2010

Keywords

• more
• nonn

Comments

The next term, if it exists, is > 100000.

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "99947".

Examples

			10^3 - 53 = 947 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-53) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

Corrected terms a(17) and a(18) by Robert Price, Dec 24 2010

a(20-22)=64436,74335,76875 from Robert Price, May 29 2011