A323112 Numbers k such that 423*2^k+1 is prime.

2, 5, 6, 8, 9, 12, 17, 24, 44, 48, 57, 68, 74, 125, 204, 272, 306, 345, 378, 488, 528, 678, 750, 974, 1140, 2274, 2928, 4532, 4533, 6173, 7784, 12500, 14436, 15404, 16406, 56730, 76332, 150317, 207956, 215652, 256686, 269598, 276024, 509720, 644966, 850217

Offset

1,1

Links

Robert Price, Table of n, a(n) for n = 1..51

Ray Ballinger, Proth Search Page

Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for 300 < k < 600

Y. Gallot, Proth.exe: Windows Program for Finding Large Primes

Wilfrid Keller, List of primes k.2^n - 1 for k < 300

Eric Weisstein's World of Mathematics, Proth Prime

Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime

Maple

select(k->isprime(423*2^k+1), [$1..1000]); # Muniru A Asiru, Jan 05 2019

Mathematica

Select[Range[1000], PrimeQ[423*2^# + 1] &]

Prog

(Python)
from sympy.ntheory.primetest import isprime
for n in range(1, 1000):
    if isprime(423*2**n+1):
        print(n, end=', ') # Stefano Spezia, Jan 05 2019

Crossrefs

Sequence in context: A273867 A047325 A102611 * A176114 A057915 A154329

Adjacent sequences: A323109 A323110 A323111 * A323113 A323114 A323115

Keyword

nonn,hard

Author

Robert Price, Jan 04 2019

Status

approved