OFFSET
1,1
COMMENTS
a(n) is even because 7*8^(2*k+1) + 1 is divisible by 3.
FORMULA
a(n) = A032353(n)/3 where this is an integer.
MATHEMATICA
Select[Range[0, 200000, 2], PrimeQ[7*8^# + 1] &]
PROG
(PARI) is(n)=ispseudoprime(7*8^n+1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Robert Price, Feb 29 2016
STATUS
approved