OFFSET
1,2
COMMENTS
Larger members of the sequence generate probable primes only.
Corresponding prime numbers are: 2, 3, 7, 23, 1367, 87383, 5592407, 1466015503703,6447604371278022265099607,.. etc.
LINKS
Henri & Renaud Lifchitz, (2^n+5)/3 PRPs [PRP Top Records]
FORMULA
a(n) = 2*A261539(n).
MATHEMATICA
Select[Range[0, 10000], PrimeQ[(2^# + 5)/3] &]
PROG
(Magma) [n: n in [0..2000] | (2^n+5) mod 3 eq 0 and IsPrime((2^n+5) div 3)];
(PARI) is(n)=ispseudoprime((2^n+5)/3) \\ Charles R Greathouse IV, Jun 07 2016
CROSSREFS
KEYWORD
nonn,more,hard
AUTHOR
Vincenzo Librandi, May 13 2016
STATUS
approved