A108365 Integers k such that 10^k - 39 is prime.

2, 5, 6, 12, 17, 19, 61, 102, 195, 447, 1250, 1329, 1935, 3930, 5837, 7176, 8724, 20881, 23936, 61868, 91920

Offset

1,1

Comments

The next term, if one exists, is > 100000. - Robert Price, Apr 25 2011

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "99961".

Links

Table of n, a(n) for n=1..21.

Makoto Kamada, List of near-repdigit-related prime numbers.

Index entries for primes involving repunits.

Example

k=2 is a term because 10^2 - 39 = 61 (prime).
k=61 is a term because 10^61 - 39 = 9999999999999999999999999999999999999999999999999999999999961 (prime).

Crossrefs

Cf. A108330, A108328.

Sequence in context: A085206 A238481 A058601 * A064765 A257805 A082552

Adjacent sequences: A108362 A108363 A108364 * A108366 A108367 A108368

Keyword

nonn,more

Author

Parthasarathy Nambi, Jul 01 2005

Extensions

a(8)-a(12) from Stefan Steinerberger, Nov 05 2005

a(13)-a(19) from Robert Price, Dec 12 2010

Edited by Ray Chandler, Dec 23 2010

a(20)-a(21) from Robert Price, Apr 25 2011

Status

approved