RosettaCodeData/Task/Arithmetic-Rational/Fermat/arithmetic-rational.fermat

for n=2 to 2^19 by 2 do
    s:=3/n;
    m:=1;
    while m<=n/3 do
        if Divides(m,n) then s:=s+1/m; fi;
        m:=m+1;
    od;
    if s=2 then !!n fi;
od;