C :

#include <stdio.h>
unsigned long long compute(int n)
{
	unsigned long long sum = 0;
	if (n == 1)
		return 1;
	else{
		sum += 2 * compute(n - 1);
	}
	return sum + 1;
}
int main(void)
{
	int num = 0;
	while (scanf("%d", &num) == 1)
	{
		printf("%llu\n", compute(num));
	}
}

C++ :

#include <iostream>
using namespace std;
int main(){
	unsigned long long a[64];
	a[0] = 1;
	for(int i=1;i<64;i++)
		a[i] = 2*a[i-1] + 1; 
	for(int n;cin>>n;)
		cout<<a[n-1]<<endl;}

Pascal :

//a[n]=a[n-1]*2+1
program p21144(Input,Output);
 const jz=10;
var
 i,j,k,t,lena,n:integer;
 a:array[1..1000] of integer;

procedure chen();
 var
  i,x:integer;
begin
  x:=0;
  for i:= 1 to lena do
    begin
     a[i]:=a[i]*2+x;
     x:=a[i] div jz;
     a[i]:=a[i] mod jz;
    end;
 if x>0 then begin a[i+1]:=x; inc(lena); end;
end;

procedure jia();
 var
  i,j,x:integer;
begin
 a[1]:=a[1]+1;
 x:=a[1] div jz;
 a[1]:=a[1] mod jz;
 i:=1;
 while x<>0 do
  begin
   inc(i);
   a[i]:=a[i]+x;
   x:=a[i] div jz;
   a[i]:=a[i] mod jz;
  end;
 if (i=lena)  then lena:=i;
end;

begin
while not eof(Input) do
begin
 readln(n);
 a[1]:=1;
 lena:=1;
 for k:=2 to n do
  begin
   chen();//*2
   //writeln('c',a[3],a[2],a[1],' ',lena);
   jia(); //+1
  end;
 for i:=lena downto 1 do
  write(a[i]);
 writeln;
end;
end.

Java :

import java.util.Scanner;
import java.math.*;
public class Main{
	public static void main(String[] args) {   
 		Scanner in=new Scanner(System.in);
 	while(in.hasNext()) {
 		int b = in.nextInt();
 		BigInteger one=new BigInteger("1");
 		BigInteger two=new BigInteger("2");
 		BigInteger x=two.pow(b).subtract(one);
 		System.out.println(x);
 	}
}}