Notes: C, E, and Ab - Key: C - Category: Tetratonic Scales
The C Four Semitone I uses four notes per octave. Because of this same reason it is a member of the so called Tetratonic -scales that have Four-note (or Four-tone). On the piano keyboard, it is made up of one black keys: Ab and two white keys: C, and E. This combination makes this scale - as well as the C Prometheus, C Prometheus Liszt, and C Prometheus Neapolitan - as great choices for composing or improvising music.
If we take a look a the key signature of the C Four Semitone I Scale we can find it has one flats and no sharps. Therefore, on sheet music you will find one accidentals on the score. The notes of this scale are: C, E, and Ab.