A082708 Numbers k such that (34*10^(k-1) - 43)/9 is a plateau prime.

3, 15, 55, 69, 85, 87, 157, 2767, 3381, 3877, 5209, 10747, 15769, 31317, 40959, 45805, 46567, 51009, 80163

Offset: 1

Author

Patrick De Geest, Apr 13 2003

Keywords

• nonn
• base
• hard
• more

Comments

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

Examples

			k=15 -> (34*10^(15-1) - 43)/9 = 377777777777773.
		

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 - 373.
• Makoto Kamada, Prime numbers of the form 377...773.
• Index entries for primes involving repunits.

Crossrefs

Cf. A082697-A082720, A056255.

Formula

a(n) = A056255(n) + 2.

Extensions

Updates from De Geest site by Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

a(18)=51009 from Ray Chandler, Nov 16 2010

a(19)=80163 from Ray Chandler, Dec 15 2010

Edited by Ray Chandler, Nov 05 2014