program oken;
uses crt;
var n,i,j,dem: longint;
begin
    clrscr;
    write('Nhap n: '); readln(n);
    write('Cac so nguyen to: ');
    for i:=1 to n do
        begin
            dem:=0;
            for j:=2 to (i div 2) do
                if (i mod j=0) then
                    dem:=dem+1;
            if dem=0 then
                write(i,' ');
        end;
    readln;
end.

uses crt;
var i,j,n:longint;
begin
clrscr;
   write('n=');readln(n);
   write('Cac so nguyen to tu 1 toi n:');
   for i:=2 to n do
      begin
         j:=2;
         while i mod j<>0 do inc(j);
         if j=i then write(i,';');
      end;
readln
end.

/////////////////////////////

Test: