OFFSET
1,2
COMMENTS
Larger k values yield probable primes.
a(8) > 100000 (if it exists). - Michael S. Branicky, Nov 11 2024
MATHEMATICA
ParallelTable[If[PrimeQ[5^(n+3) + 3^(n+2) + 2^(n+1) + 1], n, Nothing], {n, 0, 10^4}]
CROSSREFS
KEYWORD
nonn,hard,more,changed
AUTHOR
Mikk Heidemaa, Jun 07 2019
STATUS
approved