A074645 Numbers k such that A000010(k) divides A074639(k).

1, 2, 4, 6, 10, 12, 22, 24, 28, 33, 44, 48, 60, 114, 122, 153, 180, 196, 222, 228, 284, 380, 649, 876, 981, 984, 1140, 1834, 2031, 2184, 2190, 2403, 2465, 2498, 2788, 2852, 3950, 4160, 5480, 5546, 6744, 8480, 8802, 9494, 10444, 11484, 11970, 13560, 13988, 17208

Offset

1,2

Links

Table of n, a(n) for n=1..50.

Prog

(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
isok(k) = (f(k) % eulerphi(k)) == 0; \\ Michel Marcus, Jul 05 2021

Crossrefs

Cf. A000010, A074639.

Sequence in context: A194944 A133871 A068514 * A125286 A045963 A128169

Adjacent sequences: A074642 A074643 A074644 * A074646 A074647 A074648

Keyword

nonn

Author

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

Extensions

More terms from Michel Marcus, Jul 05 2021

Status

approved