A082715 Numbers k such that (71*10^(k-1) - 17)/9 is a plateau prime.

3, 5, 87, 113, 171, 567, 1689, 8903, 115811

Offset

1,1

Comments

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

References

C. Caldwell and H. Dubner, The near repdigit primes A(n-k-1)B(1)A(k), especially 9(n-k-1)8(1)9(k), Journal of Recreational Mathematics, Volume 28, No. 1, 1996-97, pp. 1-9.

Links

Table of n, a(n) for n=1..9.

Patrick De Geest, PDP Reference Table - 787.

Makoto Kamada, Prime numbers of the form 788...887.

Index entries for primes involving repunits.

Formula

a(n) = A056262(n) + 2.

Example

k=5 -> (71*10^(5-1) - 17)/9 = 78887.

Crossrefs

Cf. A082697-A082720, A056262.

Sequence in context: A107655 A182234 A308612 * A133660 A271925 A236365

Adjacent sequences: A082712 A082713 A082714 * A082716 A082717 A082718

Keyword

nonn,base,hard,more

Author

Patrick De Geest, Apr 13 2003

Extensions

115811 from Ray Chandler, Aug 05 2011

a(2)=5 corrected by Patrick De Geest, Apr 28 2013

Edited by Ray Chandler, Nov 05 2014

Status

approved