OFFSET
1,1
COMMENTS
There are no square terms, as squares are congruent to 0 or 1 modulo 3.
Products of a prime of the form 3m+1 and a prime of the form 3m+2 (the former necessarily being of the form 6m+1).
EXAMPLE
14 = 2 * 7 has 2 prime factors (counting repetitions) so is a semiprime, and 14 = 3*4 + 2, so has the form 3m+2. So 14 is in the sequence.
MATHEMATICA
Select[Range[2, 500, 3], PrimeOmega@#==2&] (* Giorgos Kalogeropoulos, Jun 02 2021 *)
PROG
(PARI) isok(m) = bigomega(m) == 2 && m % 3 == 2;
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Peter Munn, May 31 2021
STATUS
approved