A216181 - OEIS

A216181

Numbers n such that (11^n - 4^n)/7 is prime.

3, 5, 11, 17, 71, 89, 827, 22307, 45893, 63521

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OFFSET

1,1

COMMENTS

All terms are prime.

Next term > 10^5.

LINKS

MATHEMATICA

Select[Prime[Range[1, 100000]], PrimeQ[(11^# - 4^#)/7]&]

PROG

(PARI) is(n)=ispseudoprime((11^n-4^n)/7) \\ Charles R Greathouse IV, Feb 20 2017

CROSSREFS

KEYWORD

nonn,hard,more

AUTHOR

Robert Price, Mar 11 2013

STATUS

approved