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 A329584 #7 Nov 17 2019 16:06:49 %S A329584 1,3,2,4,3,5,7,5,6,9,6,10,6,8,13,10,9,15,9,12,11,18,10,15,16,14,22,18, %T A329584 15,18,24,15,25,12,27,18,28,22,18,24,20,25,21,27,18,34,23,30,28,21,37, %U A329584 24,30,39,26,33,20,39,27,43,30,29,45,30,36,40,27,48 %N A329584 phi(A327922(n))/4, for n >= 1, with phi = A000010 (Euler's totient). %C A329584 This sequence applies to the odd m >= 3 numbers collected in A327922 with 4 dividing phi(2*m) = phi(m). The analog for even m is: every even numbers m >= 4 has even phi(2*m)/2 = A062570(m/2) = 2*A055034(m/2), This means that phi(2*m)/4 = A055034(m/2), for every even m >= 4. %F A329584 a(n) = A000010(A327922(n))/4, for n >= 1. %e A329584 n = 1: A327922(1) = 5, A000010(5) = 4, hence a(1) = 1. %e A329584 n = 5: A327922(5) = 21 = 3*7, A000010(21) = 2*6 = 12, hence a(5) = 3. %t A329584 Select[EulerPhi[Range[3, 200, 2]]/4, IntegerQ] (* _Amiram Eldar_, Nov 17 2019 *) %Y A329584 Cf. A000010, A055034, A062570, A327922. %K A329584 nonn,easy %O A329584 1,2 %A A329584 _Wolfdieter Lang_, Nov 17 2019