A373494 Numbers k for which A059975(k) and A003415(k) are both multiples of 3, where A059975 is fully additive with a(p) = p-1, and A003415 is the arithmetic derivative.

1, 8, 20, 27, 36, 44, 50, 64, 68, 90, 92, 110, 116, 125, 160, 162, 164, 170, 188, 189, 198, 212, 216, 225, 230, 236, 242, 252, 275, 284, 288, 290, 306, 332, 343, 351, 352, 356, 374, 400, 404, 405, 410, 414, 425, 428, 452, 468, 470, 495, 506, 512, 513, 522, 524, 530, 540, 544, 548, 575, 578, 590, 596, 605, 630, 637

Offset: 1

Author

Antti Karttunen, Jun 10 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..10000

Crossrefs

Cf. A003415, A059975, A373492 (subsequence), A373493 (characteristic function).

Positions of multiples of 3 in A373378.

Intersection of A373385 and A327863.

Programs

PARI

isA373494 = A373493;