Guessed after just one "No"

  3  9 27  yes  (is it exponential series?)
  4 16 64  yes  (is it only odd numbers?)
  5  7  9  yes  (is it any numbers of the same parity?)
  6  7  8  yes  (is it any set of increasing numbers?)
  6  7  6  no   (just to confirm that it's x<y<z, and not something like x<=y<=z)