A374044 Non-multiples of 3 whose 2-adic valuation is a multiple of 3.

1, 5, 7, 8, 11, 13, 17, 19, 23, 25, 29, 31, 35, 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, 136, 137, 139, 143, 145, 149, 151, 152, 155, 157, 161, 163, 167, 169, 173, 175, 179, 181, 184, 185, 187

Offset

1,2

Comments

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

The asymptotic density of this sequence is 8/21. - Amiram Eldar, Jun 28 2024

Links

Antti Karttunen, Table of n, a(n) for n = 1..12000

Formula

{k | A007814(k) == 0 (mod 3), A007949(k) = 0}.

Mathematica

Select[Range[200], !Divisible[#, 3] && Divisible[IntegerExponent[#, 2], 3] &] (* Amiram Eldar, Jun 28 2024 *)

Prog

(PARI) isA374044 = A374043;

Crossrefs

Cf. A007814, A007949, A374043 (characteristic function).

Intersection of A001651 and A191257.

Subsequence of A339746, of A373992, and of A374042.

Sequence in context: A191929 A082728 A374042 * A359629 A285081 A154370

Adjacent sequences: A374041 A374042 A374043 * A374045 A374046 A374047

Keyword

nonn,easy

Author

Antti Karttunen, Jun 27 2024

Status

approved