A373478 Numbers k such that A001414(k) and A003415(k) are both multiples of 3, where A001414 is the sum of prime factors with repetition, and A003415 is the arithmetic derivative.

1, 8, 9, 14, 20, 26, 27, 35, 38, 44, 50, 62, 64, 65, 68, 72, 74, 77, 81, 86, 92, 95, 110, 112, 116, 119, 122, 125, 126, 134, 143, 146, 155, 158, 160, 161, 164, 170, 180, 185, 188, 194, 196, 203, 206, 208, 209, 212, 215, 216, 218, 221, 230, 234, 236, 242, 243, 254, 275, 278, 280, 284, 287, 290, 299, 302, 304, 305

Offset: 1

Author

Antti Karttunen, Jun 07 2024

Keywords

• nonn

Comments

A multiplicative semigroup; if m and n are in the sequence then so is m*n.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..20000

Crossrefs

Cf. A001414, A003415, A373477 (characteristic function).

Positions of multiples of 3 in A373364.

Intersection of A289142 and A327863.

Disjoint union of A373475 and A373479.

Programs

PARI

isA373478 = A373477;