Incidentally, rather than
Code:
? gettime(); foo; print(bar); gettime()
I would write
where # turns the timer on (or off). In your case this would have resulted in
Code:
? #
timer = 1 (on)
? p=21701;n=2^p-1;e=n;r=Mod(3,n)^((e))-3;[length(e),lift(r)]
time = 54,996 ms.
%1 = [679, 0]
? p=21701;n=2^p-1;e=lift(Mod(2,n-1)^(p-1));r=Mod(3,n)^((e))+3;[length(e),lift(r)]
time = 54,455 ms.
%2 = [679, 0]
(Apologies if this was known/obvious.)