import java.util.*;

public class Main {
    static final int MOD = 1000000007;
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int s = sc.nextInt();
		int kk = sc.nextInt();
		int min = n * (n - 1) * kk / 2;
		if (s < min) {
		    System.out.println(0);
		    return;
		}
		s -= min;
		int[][] dp = new int[n + 1][s + 1];
		dp[0][0] = 1;
		for (int i = 0; i * n <= s; i++) {
		    dp[1][i * n] = 1;
		}
		for (int i = 2; i <= n; i++) {
		    for (int j = 0; j <= s; j++) {
		        if (dp[i - 1][j] == 0) {
		            continue;
		        }
		        for (int k = 0; j + k * (n - i + 1) <= s; k++) {
		            dp[i][j + k * (n - i + 1)] += dp[i - 1][j];
		            dp[i][j + k * (n - i + 1)] %= MOD;
		        }
		    }
		}
		System.out.println(dp[n][s]);
	}
}