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A143279
Numbers n such that 6*5^n + 1 is prime.
3
0, 1, 2, 3, 23, 27, 33, 63, 158, 278, 290, 351, 471, 797, 8462, 28793, 266030
OFFSET
1,3
COMMENTS
Primes found and proved by PrimeForm.
All terms correspond to verified primes, that is, not merely probable primes. - Robert Price, Jan 16 2015
a(18) > 3*10^5. - Robert Price, Jan 16 2015
MATHEMATICA
Select[Range[0, 10000], PrimeQ[6*5^# + 1] &] (* Robert Price, Jan 16 2015 *)
PROG
(PARI) is(n)=ispseudoprime(6*5^n+1) \\ Charles R Greathouse IV, Jun 06 2017
CROSSREFS
Sequence in context: A085946 A280894 A042585 * A272271 A068887 A364142
KEYWORD
hard,nonn
AUTHOR
Rick L. Shepherd, Aug 04 2008
EXTENSIONS
a(17) from Robert Price, Jan 16 2015
STATUS
approved