Primal
Despite sounding (to me) irregular, the note events are actually much more regular than your stereotypical pop song that typically varies such things as the rhythm, pitches, harmony, ABBA structures, etc. The small but not too small prime numbers throw the rhythm off enough so that the longer beats (to me) are heard as a melody of sorts. A computer program might "hear" something totally different depending on how it pulls the sonic (or MIDI) events apart.
Source