−a14z−2−a14−a12z6−3a12z4 + 2a12z2 + 4a12z−2 + 9a12 + a10z8 + 4a10z6−a10z4−18a10z2−5a10z−2−19a10 + a8z8 + 7a8z6 + 18a8z4 + 21a8z2 + 2a8z−2 + 11a8