OFFSET
1,1
COMMENTS
All terms are prime.
The corresponding primes: 193, 21121, 1979713, ...
LINKS
Jon Grantham and Andrew Granville, Fibonacci primes, primes of the form 2^n-k and beyond, arXiv:2307.07894 [math.NT], 2023.
MATHEMATICA
Select[Range[1, 10000], PrimeQ[(9^# - 7^#)/2] &]
PROG
(PARI) for(n=1, 10000, if(isprime((9^n - 7^n)/2), print1(n, ", ")))
CROSSREFS
KEYWORD
nonn,more,hard
AUTHOR
Tim Johannes Ohrtmann, May 13 2016
EXTENSIONS
a(6) from Jon Grantham, Jul 29 2023
STATUS
approved