#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<set>
#include<map>
#include<vector>
#include<algorithm>
#include<queue>
#include<iostream>
using namespace std;

long long mod = 1000000007;
long long dp[2005][2005];
long long rev[2005];


long long binpow(long long a, long long n)
{
	long long ans = 1;
	while(n > 0)
	{
		if(n & 1ll)
			ans = (ans * a) % mod;
		a = (a * a) % mod;
		n /= 2;
	}
	return ans;
}

int main()
{
	rev[1] = 1;
	for(int i = 2; i <= 2000; i++) {
		rev[i] = (mod - ((rev[mod % i] * (mod / i)) % mod)) % mod;
		//if(rev[i] != binpow(i, mod - 2))
		//	printf("BA %d\n", i);
	}
	while(1)
	{
		long long  d;
		int n, x;
		scanf("%d%lld%d", &n, &d, &x);
		if(n == 0)
			break;

		int rd = min(1ll * n, d);
		//memset(dp, 0, sizeof(dp));
		dp[0][0] = 1;
		for(int i = 1; i <= rd; i++) 
		{
			/*for(int j = 1; j <= n; j++) {
				dp[j][i] = dp[j - 1][i] + dp[j - 1][i - 1] + mod - (j - x >= 0 ? dp[j - x][i - 1] : 0);
				dp[j][i] %= mod;
			}*/
			for(int j = 1; j < x; j++)
			{
				dp[j][i] = dp[j - 1][i] + dp[j - 1][i - 1];
				if(dp[j][i] >= mod)
					dp[j][i] -= mod;
			}
			for(int j = x; j <= n; j++) {
				dp[j][i] = dp[j - 1][i] + dp[j - 1][i - 1] + mod - dp[j - x][i - 1];
				while(dp[j][i] >= mod)
					dp[j][i] -= mod;
			}
		}
		long long ans = 0, cnk = 1;
		for(int i = 1; i <= rd; i++)
		{
			cnk = (((cnk * ((d - i + 1) % mod)) % mod) * rev[i]) % mod;
			ans = (ans + cnk * dp[n][i]) % mod;
		}
		printf("%lld\n", ans);
	}

	return 0;
}
