C :

#include <stdio.h>
#include <stdlib.h>
int q(m)
{
   if(m==1)
   return 1;
   else return ((q(m-1)+1)*2) ; 
} 
int main(int argc, char *argv[])
{
  int a,m;
  scanf("%d",&m);
  a=q(m);
  printf("%d",a);

  return 0;
}

C++ :

#include<iostream>
using namespace std;
int main()
{
	int n,sum=1;
	cin>>n;
	for (int i=1; i<n; i++)
		sum=2*(sum+1);
	cout<<sum<<endl;
	return 0;
}

Pascal :

var i,n,s:longint;
begin
  s:=1;
  readln(n);
  for i:=1 to n-1 do
  s:=(s+1)*2;
  writeln(s);
end.