any scale using five notes is "pentatonic" ("penta" is greek for "five"). however, the pentatonic scale which is used in most western music uses notes which do not have any semitones. a pentatonic scale starting on c will use the notes c,d,e,g,a (the 1st, 2nd, 3rd, 5th and 6th notes of a major scale).. an easy way to find such a pentatonic scale is by using all the black notes of a keyboard.