"1-Pi to 500 Decimal Places: Piano Solo. Audio with keyboard graphic. A good one to start with to familiarize yourself with how these sonifications were done. The same digit to pitch mapping was used in most of the following songs. The zero is usually not played as a note but shows up as a rest of the same duration as the notes in the particular piece. (3:11)
2 - Pi to 1,000 Decimal Places: Piano Solo. Audio with pi matrix. About four notes per second. (4:19) Update: Also an improvisation by Chis Mear based on this piece.
3 - Pi to 1,000 Decimal Places: Piano, Bass, Flute. Audio with graphics. A more complex mapping than the first two. (4:15)
4 - Pi's Digit Matrix for the First 100 Digits. Video animation, no audio. Visually explores the digit pattern in the first 1,000 digits of pi. (0:47)
5 - e to 500 Decimal Places: Piano Solo. Audio with e matrix. (1:47) "
These involved descriptions indicate some involved mathematical composition process, which Dukich doesn't go into detail describing (sooo it may not even exist and he just wants you to think he was using a complex system... maybe). You can listen and watch them for yourself on his site at http://www.tomdukich.com/math%20songs.html