OFFSET
1,1
COMMENTS
All terms are primes.
a(9) > 10^5. - Robert Price, Jan 19 2013
a(10) > 10^6. - Jon Grantham, Jul 29 2023
LINKS
Jon Grantham and Andrew Granville, Fibonacci primes, primes of the form 2^n-k and beyond, arXiv:2307.07894 [math.NT], 2023.
MATHEMATICA
k=9; Do[p=Prime[n]; f=(k^p-5^p)/(k-5); If[ PrimeQ[f], Print[p] ], {n, 1, 100}]
PROG
(PARI) is(n)=isprime((9^n-5^n)/4) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Alexander Adamchuk, Feb 27 2007
EXTENSIONS
a(7)-a(8) from Robert Price, Jan 19 2013
a(8) corrected by Robert Price, Jan 20 2013
a(9) from Jon Grantham, Jul 29 2023
STATUS
approved