A067019 Odd numbers with an odd number of prime factors (counted with multiplicity).

3, 5, 7, 11, 13, 17, 19, 23, 27, 29, 31, 37, 41, 43, 45, 47, 53, 59, 61, 63, 67, 71, 73, 75, 79, 83, 89, 97, 99, 101, 103, 105, 107, 109, 113, 117, 125, 127, 131, 137, 139, 147, 149, 151, 153, 157, 163, 165, 167, 171, 173, 175, 179, 181, 191, 193, 195, 197, 199

Offset

1,1

Comments

Subsequence of odd terms of A026424. - Michel Marcus, Jul 04 2015

The sequence a(1)=0, for n>1 a(n) is smallest number such that for all s,t,m<n a(n) != a(s)*a(t)+a(m) is the same as this one from a(3). - Anders Hellström, Jul 08 2015

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Example

a(9) = 27, which is odd with an odd number of prime factors, i.e., 3.

Prog

(PARI) isok(k) = { k%2 == 1 && bigomega(k)%2 == 1 } \\ Harry J. Smith, Apr 25 2010

Crossrefs

Intersection of A005408 and A026424.

Setwise difference A005408 \ A046337.

Cf. A353558 (characteristic function).

Positions of the terms of the form 4u+2 (A016825) in A358669 (and in A358765).

Sequence in context: A100392 A309203 A176847 * A132106 A242393 A210494

Adjacent sequences: A067016 A067017 A067018 * A067020 A067021 A067022

Keyword

nonn

Author

Shyam Sunder Gupta, Feb 16 2002

Status

approved