A213049 Primes p such that the order of 2 mod p is a square.

5, 37, 73, 101, 109, 197, 257, 577, 601, 641, 677, 727, 1601, 1801, 2593, 3137, 3389, 3457, 4057, 4357, 5477, 8101, 8837, 10369, 14401, 14407, 16901, 17957, 18253, 18433, 20809, 21317, 22501, 25601, 30977, 33857, 37447, 42437, 44101, 47629, 47653, 50177

Offset: 1

Author

Joerg Arndt, Jun 03 2012

Keywords

• nonn

Examples

			The order of 2 mod 601 is 25, which is a square, so 601 is a term.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..178

Crossrefs

Cf. A014662, A014663, A122094.

Programs

Magma

[NthPrime(n): n in [2..6275] | IsSquare(Modorder(2, NthPrime(n)))]; // Bruno Berselli, Jun 08 2012

PARI

{ forprime (p=3, 10^6,
    r = znorder(Mod(2,p));
    if ( issquare(r), print1(p,", ") );
); }