A374042 Numbers k such that A276085(k) and A328768(k) are both multiples of 3, where A276085 is the primorial base log-function, and A328768 is the first primorial based variant of arithmetic derivative.

1, 5, 7, 8, 11, 13, 17, 19, 23, 25, 27, 29, 31, 35, 36, 37, 40, 41, 43, 47, 49, 53, 55, 56, 59, 61, 64, 65, 67, 71, 73, 77, 79, 83, 85, 88, 89, 91, 95, 97, 101, 103, 104, 107, 109, 113, 115, 119, 121, 125, 127, 131, 133, 135, 136, 137, 139, 143, 145, 149, 151, 152, 155, 157, 161, 162, 163, 167, 169, 173, 175, 179

Offset

1,2

Comments

Numbers whose 3-adic valuation is not 1 and whose 2-adic and 3-adic valuations are equal modulo 3.

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..12000

Index entries for sequences related to primorial numbers

Formula

{k | A007814(k) == A007949(n) (mod 3), A007949(k) != 1}.

Prog

(PARI) isA374042 = A374041;

Crossrefs

Intersection of A339746 and A373992.

Positions of multiples of 3 in A374031.

Cf. A276085, A328768, A374041 (characteristic function), A374044 (subsequence).

Sequence in context: A013635 A191929 A082728 * A374044 A359629 A285081

Adjacent sequences: A374039 A374040 A374041 * A374043 A374044 A374045

Keyword

nonn

Author

Antti Karttunen, Jun 26 2024

Status

approved