A118818 Primes p for which there are more primitive roots below p/2 than above p/2.

223, 379, 463, 631, 691, 883, 907, 1051, 1423, 1447, 1543, 1723, 1747, 1783, 1987, 2143, 2179, 2347, 2467, 2591, 2767, 3259, 3307, 3511, 3631, 3691, 3739, 3823, 3907, 4219, 4447, 4507, 4519, 4639, 4987, 5023, 5107, 5119, 5347, 5683, 5923

Offset

1,1

Comments

All terms are of the form 4*m + 3 (see A172480 and A172490). - Emmanuel Vantieghem, Nov 07 2016

Links

Amiram Eldar, Table of n, a(n) for n = 1..1000

Example

223 is a term because it has 38 primitive roots below 111.5, but 34 above 111.5.

Mathematica

q[n_] := PrimeQ[n] && Length[(p = PrimitiveRootList[n])] > 2*Count[p, _?(# > n/2 &)]; Select[4*Range[0, 1500] + 3, q] (* Amiram Eldar, Oct 11 2021 *)

Crossrefs

Cf. A128859, A172480, A172490.

Sequence in context: A142386 A102950 A143801 * A142437 A142773 A096660

Adjacent sequences: A118815 A118816 A118817 * A118819 A118820 A118821

Keyword

nonn

Author

Don Reble, Apr 20 2007

Status

approved