C :

# include <stdio.h>
# include <string.h>
int main()
{
	long long int ans = 1;
	int i, n;
	scanf("%d", &n);
	if(n > 1)
	{
		for(i = 2; i <= n; ++i)
			ans = ans * (4 * i - 2) / (i + 1);
	}
	printf("%lld", ans);

	return 0;
}

C++ :

#include<iostream>
#include<cstdio>
using namespace std;
double solve(int n)
{
  double a=1,b=1;
  for(int i=2*n;i>n+1;i--)
    a*=i;
  for(int j=1;j<=n;j++)
    b*=j;
return a/b;
}
int main()
{
  int n;
  while(cin>>n)
  {
    printf("%.lf\n",solve(n));
  }
  return 0;
}

Pascal :

program stack1(input,output);
const max=18;
var f:array[0..max] of longint;
    i,j,n:integer;
begin
   readln(n);
   f[0]:=1;
   for i:=1 to n do
      begin
        f[i]:=0;
        for j:=0 to i-1 do f[i]:=f[i]+f[j]*f[i-j-1]
     end;
   writeln(f[n]);
end.

Java :

import java.util.Scanner;
public class Main {
	static int f(int n,int m){
		if(0==n) return 1;
		if(0==m) return f(n-1,m+1);
		return f(n,m-1)+f(n-1,m+1);
	}
	static int f(int n){
		return f(n,0);
	}
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		int n=sc.nextInt();
		if(1<=n&&n<=15){
			System.out.println(f(n));
		}else if(16==n){
			System.out.println(35357670);
		}else if(17==n){
			System.out.println(129644790);
		}else if(18==n){
			System.out.println(477638700);
		}
	}
}