代码：

var
n,i,j,s:longint;
a:array[-10..10000000]of boolean;
b:array[1..4]of longint=(1,3,7,9);
procedure dfs(s,t:longint);
var
i:longint;
 begin
 if t=n then begin if not a[s] then writeln(s);end;
 for i:=1 to 4 do 
 if not a[s*10+b[i]] then
  dfs(s*10+b[i],t+1);
 end;
 begin
 readln(n);
 s:=1;
 for i:=1 to n do s:=s*10;
a[1]:=true;
 for i:=2 to trunc(sqrt(s))do
  if not a[i] then
   for j:=i to (s) div i do
    a[i*j]:=true;
 dfs(2,1);
 dfs(3,1);
 dfs(5,1);
 dfs(7,1);
 end.