#include<bits/stdc++.h>
#define Gc() getchar()
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define eb emplace_back
#define all(x) x.begin(),x.end()
using namespace std;using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;using pii=pair<int,int>;
const int N=1000+5,M=N*2+5,K=1e7+5,mod=1e9+7,Mod=mod-1;const db eps=1e-9;const int INF=1e9+7;mt19937 rnd(263082);
#define Tp template<typename T>
#define Ts template<typename T,typename... Ar>
namespace Debug{
	Tp void _debug(char* f,T t){cerr<<f<<'='<<t<<endl;}
	Ts void _debug(char* f,T x,Ar... y){while(*f!=',') cerr<<*f++;cerr<<'='<<x<<",";_debug(f+1,y...);}
	#ifdef LOCAL
	#define gdb(...) _debug((char*)#__VA_ARGS__,__VA_ARGS__)
	#else 
	#define gdb(...) void()
	#endif
}using namespace Debug;
int n,A[N];
ll f[N][16][16][16],g[N][16][16][16];
ll pw[N];
void Solve(){
	scanf("%d",&n);
	for(int i=1;i<=n;i++) scanf("%d",&A[i]);
	for(int i=pw[0]=1;i<=n;i++) pw[i]=pw[i-1]*2%mod;
	A[n+1]=A[n]+100;
	f[1][15][15][15]=0;g[1][15][15][15]=1;
	for(int i=1;i<=n;i++){
		for(int x=0;x<=15;x++) for(int y=0;y<=15;y++) for(int z=0;z<=15;z++) if(g[i][x][y][z]||f[i][x][y][z]){
			(f[i+1][x][y][min(15,z+A[i+1]-A[i])]+=f[i][x][y][z])%=mod;
			(g[i+1][x][y][min(15,z+A[i+1]-A[i])]+=g[i][x][y][z])%=mod;
			if(x+y+z<15){
				int pt=i;while(A[pt+1]-A[i]<15-x-y-z) pt++;
				(f[pt+1][15][15][15]+=f[i][x][y][z]*pw[pt-i])%=mod;
				(g[pt+1][15][15][15]+=g[i][x][y][z]*pw[pt-i])%=mod;
			}else{
				int pt=i;while(A[pt+1]-A[i]<20) pt++;
				(f[pt+1][y][z][min(A[pt+1]-A[i]-20,15)]+=(f[i][x][y][z]+g[i][x][y][z])*pw[pt-i])%=mod;
				(g[pt+1][y][z][min(A[pt+1]-A[i]-20,15)]+=g[i][x][y][z]*pw[pt-i])%=mod;
			}
		}
	}
	ll tot=0;
	for(int x=0;x<=15;x++) for(int y=0;y<=15;y++) for(int z=0;z<=15;z++) tot+=f[n+1][x][y][z];
	printf("%lld\n",tot%mod*2%mod);
}
int main(){
	int t=1;
	// scanf("%d",&t);
	while(t--) Solve();
	cerr<<clock()*1.0/CLOCKS_PER_SEC<<'\n';
}