http://www.cnblogs.com/huangxincheng/archive/2012/08/08/2628022.html
int getlast(int sn)
{
return 2*(sn+1);
}
int main()
{
int n=9;int to=1;
while(n){
to=getlast(to);
n--; cout<<to<<endl;
}
getchar();
return 0;
}