A126043 Exponents p of the Mersenne primes 2^p - 1 (see A000043) read mod 3.

2, 0, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 2, 2, 2, 2, 1, 1, 1, 2, 1, 2, 2, 1, 2, 2

Offset: 1

Author

Artur Jasinski, Dec 17 2006

Keywords

• nonn
• more

Crossrefs

Cf. A000043, A010872 (n mod 3), A126044-A126059.

Programs

Mathematica

Array[Mod[MersennePrimeExponent@ #, 3] &, 45] (* Michael De Vlieger, Apr 07 2018 *)

PARI

forprime(p=1, 1e3, if(isprime(2^p-1), print1(p%3, ", "))) \\ Felix Fröhlich, Aug 12 2014

Formula

a(n) = A010872(A000043(n)). - Michel Marcus, Aug 12 2014

Extensions

a(45)-a(47) from Ivan Panchenko, Apr 08 2018

a(48) from Amiram Eldar, Oct 14 2024