That depends on the way the ring is defined.

For the form

**Code:**

[ing r1=(2^n,a),....

the maximum for n is 15 (not 16: less than 2^16).

For the form

**Code:**

ring r2=(2,a),...; minpoly=.....

the maximal n is the maximal degree of the minpoly, which is

at least 65536.

That depends on the way the ring is defined.

For the form

[code][ing r1=(2^n,a),....[/code]

the maximum for n is 15 (not 16: less than 2^16).

For the form

[code]ring r2=(2,a),...; minpoly=.....[/code]

the maximal n is the maximal degree of the minpoly, which is

at least 65536.