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 A354190 #9 May 20 2022 09:02:26 %S A354190 1,4,2,12,4,8,4,8,6,20,8,24,12,16,16,40,20,24,4,48,16,40,16,16,40,48, %T A354190 8,48,8,80,16,240,32,100,32,72,28,16,48,40,48,64,32,96,24,80,32,80, %U A354190 112,160,80,156,100,32,80,32,16,40,16,192,40,64,24,148,96,160,20,240,64,160,80,48,22,112,80,48,64,192,16 %N A354190 a(n) = phi(A267099(sigma(n))), where A267099 is fully multiplicative involution swapping the positions of 4k+1 and 4k+3 primes. %H A354190 Antti Karttunen, <a href="/A354190/b354190.txt">Table of n, a(n) for n = 1..19683</a> %F A354190 a(n) = A354102(A000203(n)) = A000010(A267099(A000203(n))). %F A354190 a(n) = A354191(n) + A354102(n). %o A354190 (PARI) A354190(n) = eulerphi(A267099(sigma(n))); \\ Uses the program given in A267099. %Y A354190 Cf. A000010, A000203, A267099, A354102, A354191. %Y A354190 Cf. also A062401. %K A354190 nonn %O A354190 1,2 %A A354190 _Antti Karttunen_, May 19 2022