A082707 Numbers k such that (32*10^(k-1) - 23)/9 is a plateau prime.

3, 9, 141, 231, 427, 463, 727, 1975, 7231, 45861, 47305

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..11.

Patrick De Geest, PDP Reference Table - 353.

Makoto Kamada, Prime numbers of the form 355...553.

Index entries for primes involving repunits.

Formula

a(n) = A056254(n) + 2.

Example

k=9 -> (32*10^(9-1) - 23)/9 = 355555553.

Crossrefs

Cf. A082697-A082720, A056254.

Sequence in context: A288757 A289900 A235062 * A087193 A348141 A217638

Adjacent sequences: A082704 A082705 A082706 * A082708 A082709 A082710

Keyword

nonn,base,hard,more

Author

Patrick De Geest, Apr 13 2003

Extensions

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

Edited by Ray Chandler, Nov 05 2014

Status

approved