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 A358043 #34 Nov 18 2022 02:42:18 %S A358043 15,16,17,20,24,30,32,34,35,39,40,41,45,48,51,52,55,56,60,64,65,68,70, %T A358043 72,73,75,78,80,82,84,85,87,88,89,90,91,95,96,97,100,102,104,105,110, %U A358043 111,112,113,115,116,117,119,120,123,128,130,132,135,136,137,140,143 %N A358043 Numbers k such that phi(k) is a multiple of 8. %F A358043 A000010(a(n)) == 0 (mod 8). %t A358043 Select[Range[150], Divisible[EulerPhi[#], 8] &] (* _Amiram Eldar_, Oct 27 2022 *) %o A358043 (Python) %o A358043 from sympy.ntheory import totient %o A358043 def isok(n): return totient(n) % 8 == 0 %o A358043 (PARI) isok(k) = Mod(eulerphi(k), 8) == 0; \\ _Michel Marcus_, Oct 27 2022 %Y A358043 Cf. A000010 (phi), A053574 (its 2-adic valuation), A037074 (a subsequence). %Y A358043 Totient multiples: A066498 (3), A172019 (4), A066500 (5), A066502 (7), A332512 (12). %K A358043 nonn %O A358043 1,1 %A A358043 _Darío Clavijo_, Oct 26 2022