phil1882,

1) The sequence starts off with "2," not "1," because 1 is not a prime number.

2) There are commas between the numbers in the sequence and a comma before the ellipsis.

3) You are missing the number 18. 18 = 2*3*3 (The number of prime factors is odd.)

Therefore, the sequence is:

2, 3, 5, 7, 8, 11, 12, 13, 17, 18, 19, 20, 23, 27, 28, 29, 30, 31, ...