May be someone need it.

#include<iostream>
#include<math.h>
using namespace std;
int cnk(int k,int n)
{
    double res=1;
    for(int i=1;i<=k;++i)
        res=res*(n-k+i)/i;
    return res;
}
int hnk(int k,int n)
{
    return cnk(k,n+k-1);
}
int main()
{
    int n;
    cin>>n;
    int n_2=n/2,sum,n_9=n_2*9,e,res=0;
    for(int i=0;i<=n_9;++i)
    {
        sum=0;
        e=1;
        for(int j=1;j<=i/10;++j)
        {
            sum+=e*cnk(j,n_2)*hnk(i-j*10,n_2);
            e*=-1;
        }
        res+=pow(hnk(i,n_2)-sum,2.);
    }
    cout<<res;
    return 0;
}

//cnk(k,n)=n!/k!/(n-k)!

Edited by author 28.04.2012 22:48