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 A354102 #18 May 19 2022 16:42:48
%S A354102 1,1,4,2,2,4,12,4,20,2,16,8,6,12,8,8,10,20,28,4,48,16,36,16,6,6,100,
%T A354102 24,18,8,40,16,64,10,24,40,22,28,24,8,30,48,52,32,40,36,60,32,156,6,
%U A354102 40,12,42,100,32,48,112,18,72,16,46,40,240,32,12,64,88,20,144,24,96,80,58,22,24,56,192,24,100,16,500
%N A354102 a(n) = phi(A267099(n)), where A267099 is fully multiplicative involution swapping the positions of 4k+1 and 4k+3 primes, and phi is Euler totient function.
%H A354102 Antti Karttunen, <a href="/A354102/b354102.txt">Table of n, a(n) for n = 1..19683</a>
%F A354102 Multiplicative with a(p^e) = (q-1) * q^(e-1), where q = A267101(A000720(p)).
%F A354102 a(n) = A000010(A267099(n)).
%F A354102 a(n) = Sum_{d|n} A008683(n/d) * A267099(d).
%F A354102 a(n) = A354101(n) + A000010(n) = A354190(n) - A354191(n).
%F A354102 For all n >= 0, a(4n+2) = a(2n+1).
%o A354102 (PARI) A354102(n) = eulerphi(A267099(n)); \\ Uses the program given in A267099.
%Y A354102 Möbius transform of A267099.
%Y A354102 Cf. A000720, A008683, A267101, A354101, A354103, A354104 (Dirichlet inverse), A354105 (sum with it), A354106, A354107 (a(n) mod 4), A354190, A354191.
%Y A354102 Coincides with A000010 on A354189.
%K A354102 nonn,mult
%O A354102 1,3
%A A354102 _Antti Karttunen_, May 18 2022