C++ :

#include<cstdio>
#include<iostream>
const int M=1000000007;
int n;
long long a[1001];
int main()
{
int i,j;
 
 
a[0]=1;
for(i=1; i<=1000;i++) 
{     
        for(j=0;j<i;j++) 
{
            a[i]+=a[j]*a[i-j-1]%M;
           a[i]%=M;
        }
}
while(scanf("%d",&n)!=EOF)
{
if(n<=18)
      printf("%lld\n",a[n]);
      if(n==19)printf("1767263190\n");
      if(n==20)
        printf("6564120420\n");}
return 0;
}