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

1,1

Comments

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

References

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

Links

Table of n, a(n) for n=1..19.

Patrick De Geest, PDP Reference Table - 373.

Makoto Kamada, Prime numbers of the form 377...773.

Index entries for primes involving repunits.

Formula

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

Example

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

Crossrefs

Cf. A082697-A082720, A056255.

Sequence in context: A265974 A099581 A026696 * A093925 A117960 A176288

Adjacent sequences: A082705 A082706 A082707 * A082709 A082710 A082711

Keyword

nonn,base,hard,more

Author

Patrick De Geest, Apr 13 2003

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

Status

approved