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 A354101 #9 May 20 2022 09:02:03 %S A354101 0,0,2,0,-2,2,6,0,14,-2,6,4,-6,6,0,0,-6,14,10,-4,36,6,14,8,-14,-6,82, %T A354101 12,-10,0,10,0,44,-6,0,28,-14,10,0,-8,-10,36,10,12,16,14,14,16,114, %U A354101 -14,8,-12,-10,82,-8,24,76,-10,14,0,-14,10,204,0,-36,44,22,-12,100,0,26,56,-14,-14,-16,20,132,0,22,-16 %N A354101 a(n) = phi(A267099(n)) - phi(n), where A267099 is fully multiplicative involution swapping the positions of 4k+1 and 4k+3 primes, and phi is Euler totient function. %H A354101 Antti Karttunen, <a href="/A354101/b354101.txt">Table of n, a(n) for n = 1..19683</a> %F A354101 a(n) = A354102(n) - A000010(n) = A000010(A267099(n)) - A000010(n). %o A354101 (PARI) A354101(n) = (eulerphi(A267099(n)) - eulerphi(n)); \\ Uses the program given in A267099. %Y A354101 Cf. A000010, A267099, A354102, A354189 (positions of 0's). %K A354101 sign,look %O A354101 1,3 %A A354101 _Antti Karttunen_, May 19 2022