A082698 Numbers k such that (13*10^(k-1) - 31)/9 is a plateau prime.

7, 67, 1255, 8407, 67039

Offset

1,1

Comments

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

a(6) > 2*10^5. - Tyler Busby, Feb 02 2023

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..5.

Patrick De Geest, PDP Reference Table - 141.

Makoto Kamada, Prime numbers of the form 144...441.

Index entries for primes involving repunits.

Formula

a(n) = A056245(n+1) + 2.

Example

k=7 -> (13*10^(7-1) - 31)/9 = 1444441.

Crossrefs

Cf. A056245, A082697-A082720.

Sequence in context: A082578 A291814 A253386 * A182127 A093170 A294664

Adjacent sequences: A082695 A082696 A082697 * A082699 A082700 A082701

Keyword

nonn,base,more

Author

Patrick De Geest, Apr 13 2003

Extensions

A new PRP term from Serge Batalov, Nov 02 2008

Edited by Ray Chandler, Nov 04 2014

Status

approved