login
A067019
Odd numbers with an odd number of prime factors (counted with multiplicity).
17
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
EXAMPLE
a(9) = 27, which is odd with an odd number of prime factors, i.e., 3.
PROG
(PARI) { n=0; forstep (m=1, 10^10, 2, if (bigomega(m)%2 == 1, write("b067019.txt", n++, " ", m); if (n==1000, return)) ) } \\ 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
KEYWORD
nonn
AUTHOR
Shyam Sunder Gupta, Feb 16 2002
STATUS
approved