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 A027695 #19 Nov 30 2024 06:27:47
%S A027695 1,2,4,12,32,120,288,1512,4096,15552,48000,240064,552960,3439800,
%T A027695 9483264,35640000,134217728,673699800,1451188224,9644765256,
%U A027695 23685120000,115605729792,401556013056,1996264531840,4566087106560,26244000000000,89961392102400,356237685227520
%N A027695 Number of primitive polynomials of degree n over GF(4).
%H A027695 Amiram Eldar, <a href="/A027695/b027695.txt">Table of n, a(n) for n = 0..1122</a> (terms 0..150 from Andrew Howroyd)
%F A027695 a(n) = A295501(n)/n = 2*A027742(n) for n >= 1. - _Amiram Eldar_, Nov 30 2024
%p A027695 with(numtheory): seq(`if`(n=0, 1, phi(4^n-1)/n), n=0..27);
%t A027695 Join[{1}, Array[EulerPhi[4^# - 1]/# &, 30]] (* _Paolo Xausa_, Jun 17 2024 *)
%o A027695 (PARI) a(n) = if(n==0, 1, eulerphi(4^n-1)/n) \\ _Andrew Howroyd_, Feb 01 2024
%Y A027695 Column k=4 of A369291.
%Y A027695 Cf. A027742, A295501.
%K A027695 nonn
%O A027695 0,2
%A A027695 _N. J. A. Sloane_
%E A027695 a(24) onwards from _Andrew Howroyd_, Feb 01 2024