/* 
 *     Author:  srtry
 *     Created: 2025-10-12T09:51:49+09:00
 *     Coding:  utf-8-unix
 */

use proconio::input;
use std::io::{stdout,Write,BufWriter};

const big:usize = 1000000007;
const n_max:usize = 100;
const s_max:usize = 20000;
const k_max:usize = 100;

fn main() {
    input!{
        n:usize, s:usize, k:usize
    }

    let out = stdout();
    let mut out = BufWriter::new(out.lock());
    
    let mut ans:usize = 0;
    for p0 in 0..=s {
        let mut dp:[usize;s_max+1] = [0;s_max+1];
        dp[0] = 1;
        let b:usize = if s >=p0*n + n*(n-1)*k/2 {
            s - p0*n - n*(n-1)*k/2
        } else {
            break;
        };
        for i in 1..=(n-1) {
            for j in i..=b {
                dp[j] = (dp[j] + dp[j-i])%big;
            }
        }
        ans += dp[b]%big;
    }
    write!(out, "{}", ans%big).unwrap();
}