A027741 Number of primitive polynomials of degree n over GF(5).

1, 2, 4, 20, 48, 280, 720, 5580, 14976, 99360, 291200, 2219460, 5184000, 46950120, 139991040, 876960000, 2752708608, 22384531584, 55435726080, 499226178000, 1280348160000, 10957459615200, 34031246515200, 259121741860800, 630789120000000, 5255180000000000

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 0..100

Crossrefs

Column k=5 of A369291.

Programs

Maple

with(numtheory): seq(`if`(n=0, 1, phi(5^n-1)/n), n=0..25);

Mathematica

Join[{1}, Array[EulerPhi[5^# - 1]/# &, 25]] (* Paolo Xausa, Jun 17 2024 *)

PARI

a(n) = if(n==0, 1, eulerphi(5^n-1)/n) \\ Andrew Howroyd, Feb 01 2024

Extensions

a(23) onwards from Andrew Howroyd, Feb 01 2024