A272781 - OEIS

A272781

Numbers n such that 6^n-5^(n+1) is prime.

9, 14, 32, 48, 78, 85, 108, 134, 834, 1701, 2275, 3103, 5795, 10307, 17243, 24045, 31085, 32613, 40014

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OFFSET

1,1

COMMENTS

a(20) > 10^5.

LINKS

EXAMPLE

9 is a member since 6^9 - 5^10 = 10077696 - 9765625 = 312071 which is a prime number.

MATHEMATICA

Select[Range[0, 100000], PrimeQ[6^# - 5^(# + 1)] &]

PROG

(PARI) is(n)=ispseudoprime(6^n-5^(n+1)) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

KEYWORD

nonn,more

AUTHOR

Robert Price, May 06 2016

STATUS

approved