A082699 Numbers k such that (14*10^(k-1) - 41)/9 is a plateau prime.

3, 5, 21, 33, 401, 563, 7017, 37685

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=21 -> (14*10^(21-1) - 41)/9 = 155555555555555555551.
		

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 - 151.
• Makoto Kamada, Prime numbers of the form 155...551.
• Index entries for primes involving repunits.

Crossrefs

Cf. A056246, A068646, A082697-A082720.

Formula

a(n) = A056246(n+1) + 2.

Extensions

37685 from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

Edited by Ray Chandler, Nov 04 2014