Just a brief remark that if $M=3$, M=2$and the constant term is$\pm2$, then these are called Garsia numbers. It is known that$z=1$is a limit point for this set (and some computational results as well). Perhaps, you'll find the following recent paper useful as far as the techniques are concerned. 1 Just a brief remark that if$M=3$, then these are called Garsia numbers. It is known that$z=1\$ is a limit point for this set (and some computational results as well). Perhaps, you'll find the following recent paper useful as far as the techniques are concerned.