# include <bits/stdc++.h>
using namespace std;
const long long maxn = 100005;
const long long MOD = 1e9+7;
long long dp[maxn][2];
long long p[305];
int main()
{
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  freopen("duel.in","r",stdin);
 freopen("duel.out","w",stdout);
long long n,m,i,j;
cin>>n;
for(i=1;i<=n;i++)
{
    cin>>p[i];
    p[i]*=2;
}

long long sum = n*(n+1)/2;
long long all= sum*2;
bool fl=1;
dp[0][0] = 1;
long long up = 0;
for(i=1;i<n;i++)
{
    for(j = 0; j<= sum; j++)
    {
        if(up-j>sum){dp[j][fl] = 0;dp[j][!fl]=0;}
        else
         dp[j][fl] = dp[j][!fl];
    }
    //fl = !fl;



    for(j=0;j<sum;j++)
    {
        if(j+p[i]>sum)break;
        dp[j+p[i]][fl] = (dp[j+p[i]][fl]+dp[j][!fl])%MOD;
    }
     for(j=0;j<sum;j++)
    {
        if(j+p[i]/2>sum)break;
        dp[j+p[i]/2][fl] = (dp[j+p[i]/2][fl]+dp[j][!fl])%MOD;
    }
//for(j=0;j<=sum;j++)
    //    cout<<i<<" "<<j<<" "<<dp[j][fl]<<endl;
        up+=p[i];
    fl = !fl;
}
long long ans =0;
for(i=1;i<=sum;i++)
    if(up-i<=sum)
{
    if((i+p[n])!=sum&&i!=sum&&(i+p[n]/2)!=sum)
     ans = (ans + 3*dp[i][!fl])%MOD;
     else
     ans = (ans + 2*dp[i][!fl])%MOD;

}

cout<<ans<<endl;
return 0;
}