login
Numbers k such that A000010(k) divides A074639(k).
1

%I #12 Jul 05 2021 15:06:48

%S 1,2,4,6,10,12,22,24,28,33,44,48,60,114,122,153,180,196,222,228,284,

%T 380,649,876,981,984,1140,1834,2031,2184,2190,2403,2465,2498,2788,

%U 2852,3950,4160,5480,5546,6744,8480,8802,9494,10444,11484,11970,13560,13988,17208

%N Numbers k such that A000010(k) divides A074639(k).

%o (PARI) f(n) = my(v=select(x->gcd(x, n)==1, [1..n-1])); vecsum(apply(x->(x*lift(1/Mod(x,n))-1)/n, v)); \\ A074639

%o isok(k) = (f(k) % eulerphi(k)) == 0; \\ _Michel Marcus_, Jul 05 2021

%Y Cf. A000010, A074639.

%K nonn

%O 1,2

%A Michele Dondi (bik.mido(AT)tiscalinet.it), Sep 18 2002

%E More terms from _Michel Marcus_, Jul 05 2021