#include<stdio.h>
#define I int
I n,s,k,f[101][20001],M;I F(I N,I M){return f[N][M]*(M>=0);}I main(I N){scanf("%d%d%d",&n,&s,&k);s-=k*n*(n-1)/2;f[0][0]=1;for(;N<=n;N++)for(M=0;M<=s;M++)f[N][M]=(F(N,M-N)+F(N-1,M))%1000000007;N=!printf("%d\n",F(n,s));}