#include<bits/stdc++.h>
#define vectorwyx maze
namespace vectorwyx{
#define pii pair<int,int>
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define mk make_pair
#define sml(x,y) (x=min(x,y))
#define big(x,y) (x=max(x,y))
#define ll long long
#define uint unsigned
#define ull unsigned long long
#define umap unordered_map
#define db double
#define fo(i,x,y) for(int i=(x);i<=(y);++i)
#define go(i,x,y) for(int i=(x);i>=(y);--i)
#define ptc putchar
#define gtc getchar
#define emp emplace
#define re return
#define co continue
#define brk break
#define HH (ptc('\n'))
#define bctz __builtin_ctz
#define bclz __builtin_clz
#define bppc __builtin_popcount
using namespace std;
ll seed=chrono::system_clock::now().time_since_epoch().count();
mt19937 rnd(seed);
inline int rm(int x,int y){return (int)(rnd()%(y-x+1ll)+x);}
inline int read(){signed ch=getchar();int x=0,f=1;while(!isdigit(ch)){if(ch==(int)('-'))f=-1;ch=getchar();}while(isdigit(ch)){x=(x<<1)+(x<<3)+(ch^48);ch=getchar();}return x*f;}
template<typename T> void out(T *a,int l,int r){fo(i,l,r) cout<<*(a+i)<<' ';puts("");}

const int N=1005,mod=1e9+7;
#define modS(x) (x=x>=mod?x-mod:x)
#define add(x,y) (x+=y,modS(x))
int a[N],n;
pii f[75][75][75],g[75][75][75];

void Add(pii &x,pii &y){add(x.fi,y.fi),add(x.se,y.se);}

signed main(){
    cin>>n;fo(i,1,n) a[i]=read();
    f[0][0][0]=mk(1,0);
    fo(i,1,n){
        fo(j,0,74) fo(k,j,74) fo(w,k,74) g[j][k][w]=mk(0,0);
        fo(j,0,74) fo(k,j,74) fo(w,k,74) if(f[j][k][w].fi){
            int d=a[i]-a[i-1];
            Add(g[max(0,j-d)][max(0,k-d)][max(0,w-d)],f[j][k][w]);
            if(j>=d){
                Add(g[j-d][k-d][w-d],f[j][k][w]);
                co;
            }
            f[j][k][w].se+=f[j][k][w].fi;
            Add(g[max(19,k-d)][max(39,w-d)][74],f[j][k][w]);
            /*if(w<d) Add(g[19][39][74],f[j][k][w]);
            else if(k<d) Add(g[19][max(39,w-d)][74],f[j][k][w]);
            else if(j<d) Add(g[max(19,k-d)][max(39,w-d)][74],f[j][k][w]);
            if(a[i-1]+j<a[i]){
                int x1=max(19,k-(a[i]-a[i-1])),x2=max(w+a[i-1]-a[i],max(39,k+a[i-1]+20-a[i]));
                int x3=;
            }*/
        }
        fo(j,0,74) fo(k,j,74) fo(w,k,74) f[j][k][w]=g[j][k][w];
    }
    int ans=0;
    fo(j,0,74) fo(k,j,74) fo(w,k,74) add(ans,f[j][k][w].se);
    cout<<ans*2%mod;
    return 0;
}
}
/*
3
1 8 20
-------------------------------------------------
*/










signed main(){re vectorwyx::main();}