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A108468
Numbers k such that (1/9)*(-1 + 10^k) + k is prime.
0
1, 2, 8, 10, 20, 590, 1058
OFFSET
1,2
COMMENTS
Some of the larger entries may only correspond to probable primes.
a(8) > 6000. - Tyler NeSmith, May 09 2021
a(8) > 10^5. - Michael S. Branicky, Sep 27 2024
PROG
(PARI) is(n)=ispseudoprime((10^n-1)/9+n) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Cf. A110369.
Sequence in context: A032356 A114272 A193266 * A165593 A127219 A122208
KEYWORD
more,nonn
AUTHOR
Jason Earls, Jul 25 2005
STATUS
approved