A082700 Numbers k such that (15*10^(k-1) - 51)/9 is a plateau prime.

5, 13, 17, 19, 37, 53, 73, 101, 6233, 24029, 40223, 66395

Offset: 1

Author

Patrick De Geest, Apr 13 2003

Keywords

• nonn
• base
• more

Comments

Prime versus probable prime status and proofs are given in the author's table.

Examples

			k=13 -> (15*10^(13-1) - 51)/9 = 1666666666661.
		

References

• C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.

Links

• Patrick De Geest, PDP Reference Table - 161.
• Makoto Kamada, Prime numbers of the form 166...661.
• Index entries for primes involving repunits.

Crossrefs

Cf. A056247, A068647, A082697-A082720.

Programs

PARI

is(n)=ispseudoprime(2*(10^n-1)/3-5*(10^(n-1)+1)) || ispseudoprime(15*10^(n-1)-51)/9 \\ Charles R Greathouse IV, Feb 07 2013

Formula

a(n) = A056247(n+1) + 2.

Extensions

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

Edited by Ray Chandler, Nov 04 2014