C :

#include<stdio.h>
#include<stdlib.h>
int po(int x,int y)
{
    int i=0;
    int j=x;
    for(i=0;i<y-1;i++)
    {
        x*=j;
    }
    return x;
}
int main()
{
    int po(int,int);
    int *a;
    int b=0;
    int sum=0;
    int p=1;
    int i=0;
    while(scanf("%d",&b)!=EOF)
    {
        a=(int *)malloc(b*sizeof(int));
        sum=0;
        p=1;
        for(i=1;i<=b;i++)
        {
            sum+=2*p;
            p=po(10,i)+p;
        }
        printf("%d\n",sum);
    }
    return 0;
}

C++ :

#include<iostream>
#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
int main()
{
int a,b=2,c=0;
cin>>a;
for(int i=0;i<a;i++)
{
        c+=b;
        b=10*b+2;
}
cout<<c<<endl;
return 0;
}

Java :

import java.util.Scanner;

public class Main {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		Scanner input = new Scanner(System.in);
		
		int N = input.nextInt();
		int j ;
		double sum = 0,n;
		for(int i = 1; i <= N; i ++){
			n = 0;
			j = i;
			while(j != 0){
				n = n + 2*Math.pow(10,j-1);
				j --;
			}
			sum += n;
		}
		System.out.println((int)sum);
		input.close();
	}
	
	

}

Python :

a = map(lambda x:int(x), raw_input().split())

a =a[0]

sn = 0
for i in range(a):
    sn += int('2'*(i+1))
print sn