A108049 Integers k such that 10^k + 43 is a prime number.

1, 5, 37, 253, 1129, 1441, 35393

Offset: 1

Author

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

Keywords

• nonn
• more
• hard

Comments

a(8) > 10^5. - Robert Price, Nov 01 2013

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "10043".

Examples

			k=5 is a term because 10^5 + 43 = 100043, which is prime.
		

Links

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

Crossrefs

Cf. A049054, A088274, A088275.

Programs

Mathematica

Select[Range[2*10^3],PrimeQ[10^#+43]&] (* Vladimir Joseph Stephan Orlovsky, Apr 29 2008 *)

PARI

is(n)=ispseudoprime(10^n+43) \\ Charles R Greathouse IV, Apr 28 2015

Extensions

a(7)=35393 from Robert Price, Mar 16 2010

Edited by Ray Chandler, Dec 23 2010