A082716 Numbers k such that (72*10^(k-1) - 27)/9 is a plateau prime.

3, 5, 29, 157, 323, 353, 1213, 1285, 7985, 15193, 84773, 119931, 148861

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=5 -> (72*10^(5-1) - 27)/9 = 79997.
		

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 - 797.
• Makoto Kamada, Prime numbers of the form 799...997.
• Index entries for primes involving repunits.

Crossrefs

Cf. A082697-A082720, A056263.

Formula

a(n) = A056263(n) + 2.

Extensions

a(11)=84773 from Ray Chandler, Jan 03 2011

a(12)=119931 from Ray Chandler, Apr 01 2011

a(13)=148861 from Ray Chandler, Apr 09 2011

Edited by Ray Chandler, Nov 04 2014