This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A027741 #12 Jun 17 2024 11:04:03
%S A027741 1,2,4,20,48,280,720,5580,14976,99360,291200,2219460,5184000,46950120,
%T A027741 139991040,876960000,2752708608,22384531584,55435726080,499226178000,
%U A027741 1280348160000,10957459615200,34031246515200,259121741860800,630789120000000,5255180000000000
%N A027741 Number of primitive polynomials of degree n over GF(5).
%H A027741 Andrew Howroyd, <a href="/A027741/b027741.txt">Table of n, a(n) for n = 0..100</a>
%p A027741 with(numtheory): seq(`if`(n=0, 1, phi(5^n-1)/n), n=0..25);
%t A027741 Join[{1}, Array[EulerPhi[5^# - 1]/# &, 25]] (* _Paolo Xausa_, Jun 17 2024 *)
%o A027741 (PARI) a(n) = if(n==0, 1, eulerphi(5^n-1)/n) \\ _Andrew Howroyd_, Feb 01 2024
%Y A027741 Column k=5 of A369291.
%K A027741 nonn
%O A027741 0,2
%A A027741 _N. J. A. Sloane_
%E A027741 a(23) onwards from _Andrew Howroyd_, Feb 01 2024