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 A350317 #13 Oct 01 2023 13:59:07 %S A350317 1,10,18,46,58,70,78,82,102,106,110,130,136,148,166,178,190,220,222, %T A350317 226,238,250,262,268,270,282,292,310,316,330,342,346,358,378,382,418, %U A350317 430,438,442,466,478,486,490,498,502,508,522,556,562,568,586,598,606,618 %N A350317 Totient numbers k such that 5*k is a nontotient. %H A350317 Winston de Greef, <a href="/A350317/b350317.txt">Table of n, a(n) for n = 1..10000</a> %e A350317 10 is a term since 10 = phi(11) = phi(22), but phi(n) = 5*10 = 50 has no solution. %e A350317 18 is a term since 18 = phi(19) = phi(27) = phi(38) = phi(54), but phi(n) = 5*18 = 90 has no solution. %o A350317 (PARI) isA350317(n) = istotient(n) && !istotient(5*n) %Y A350317 Totient numbers k such that m*k is a nontotient: A350316 (m=3), this sequence (m=5), A350318 (m=7), A350319 (m=9), A350320 (m=10), A350321 (m=14). %Y A350317 Cf. A002202, A005277. %K A350317 nonn %O A350317 1,2 %A A350317 _Jianing Song_, Dec 24 2021