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A110285
Numbers n such that n*10^n + n - 1 is prime.
0
168, 760, 2154, 9172
OFFSET
1,1
COMMENTS
Not proved, only Fermat and Lucas PRPs. Next term is greater than 12000. Concerning primes of the form n * 10^n + n + 1, only n=42 yields one for all n up to 7700.
PROG
(PARI) is(n)=ispseudoprime(n*10^n+n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A234816 A245868 A251461 * A302887 A235071 A235064
KEYWORD
more,nonn
AUTHOR
Jason Earls, Sep 07 2005
STATUS
approved