A082718 Numbers k such that (83*10^(k-1) + 61)/9 is a depression prime.

3, 7, 13, 111, 3609, 37785

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 -> (83*10^(13-1) + 61)/9 = 9222222222229.
		

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 - 929.
• Makoto Kamada, Prime numbers of the form 922...229.
• Index entries for primes involving repunits.

Crossrefs

Cf. A082697-A082720, A056265, A068651.

Formula

a(n) = A056265(n) + 2.

Extensions

37785 from Patrick De Geest, Jun 26 2005

Edited by Ray Chandler, Oct 20 2010

Edited by Ray Chandler, Nov 04 2014