A256396 Primes p such that p divides 3*2^k + 1 for some k >= 0.
2, 5, 7, 11, 13, 19, 29, 37, 53, 59, 61, 67, 79, 83, 97, 101, 103, 107, 131, 139, 149, 163, 173, 179, 181, 193, 197, 199, 211, 227, 269, 271, 293, 307, 313, 317, 347, 349, 367, 373, 379, 389, 409, 419, 421, 439, 443, 461, 463, 467, 487, 491, 499, 509, 523, 541, 547, 557, 563, 577, 587
Offset: 1
Keywords
Links
- Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
Programs
-
PARI
is(n)=if(!isprime(n), return(0)); if(n<5, return(n==2)); my(m=Mod(2,n)); while(m!=1, if(m==-3, return(1),m*=2)); 0 \\ Charles R Greathouse IV, Jun 03 2015
Formula
A prime p is in the sequence if and only if -3 == 2^k (mod p).
Comments