OFFSET
1,2
EXAMPLE
5 is in the sequence because (2^5 + 5 - 1)*2^5 + 1 = 1153 is prime.
MATHEMATICA
lst={}; Do[If[PrimeQ[(2^n + n-1)*2^n+1], AppendTo[lst, n]], {n, 10000}]; lst
PROG
(PARI) is(n)=ispseudoprime((2^n+n-1)<<n+1) \\ Charles R Greathouse IV, Feb 17 2017
(Python)
from sympy import isprime
def afind(limit, startk=1):
pow2 = 2**startk
for k in range(startk, limit+1):
if isprime((pow2 + k - 1)*pow2 + 1):
print(k, end=", ")
pow2 *= 2
afind(3000) # Michael S. Branicky, Jan 11 2022
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Michel Lagneau, Nov 30 2011
EXTENSIONS
a(8) from Michael S. Branicky, Jan 11 2022
a(9) from Michael S. Branicky, Apr 09 2023
STATUS
approved