#include<bits/stdc++.h>
// #define int ll
#define ll long long
#define fr(i,j,k) for(register int i=j;i<=k;++i)
#define rf(i,j,k) for(register int i=j;i>=k;--i)
#define foredge(i,j) for(register int i=head[j];i;i=e[i].nxt)
#define pb push_back
#define Times printf("Time:%.3lf\n",clock()/CLOCKS_PER_SEC)
#define pii pair<int,int>
#define mk make_pair
using namespace std;
inline int read(){
	int x=0;
	bool f=0;
	char c=getchar();
	while(!isdigit(c)) f|=(c=='-'),c=getchar();
	while(isdigit(c)) x=(x<<3)+(x<<1)+(c^48),c=getchar();
	return f?-x:x;
}
inline void write(int x){
    if(x<0){putchar('-');x=-x;}
    if(x>9)write(x/10);
    putchar(x%10+'0');
}
inline void writeln(int x){write(x); puts("");}
inline void writepl(int x){write(x); putchar(' ');}
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
inline int randfind(int l,int r){return rnd()%(r-l+1)+l;}
const int Maxn=2e3+10,mod=1e9+7;
int n,val[Maxn];
inline void add(int &x,int y){x+=y;if(x>=mod) x-=mod;}
int f[Maxn][Maxn][2];
int S[Maxn];
inline void work(){
    fr(i,1,n) val[i]=read();
	fr(i,0,n) fr(j,0,n) fr(k,0,1) f[i][j][k]=0;
	fr(i,1,n){
		f[2][i][0]=1;f[2][i][1]=i-1;
	}
	fr(i,3,n){
		fr(j,1,n) S[j]=(S[j-1]+f[i-1][j][1])%mod;
		fr(k,1,n) add(f[i][k][1],1ll*S[k-1]*val[k]%mod);
		fr(j,1,n) S[j]=(S[j-1]+1ll*f[i-1][j][0]*j%mod)%mod;
		fr(k,1,n) add(f[i][k][1],1ll*S[k-1]*val[k]%mod);
		S[n+1]=0;rf(j,n,1) S[j]=(S[j+1]+1ll*f[i-1][j][0]*val[j]%mod)%mod;
		fr(k,1,n) add(f[i][k][1],1ll*S[k]*(k-1)%mod);
		S[n+1]=0;rf(j,n,1) S[j]=(S[j+1]+1ll*f[i-1][j][0]*val[j]%mod)%mod;
		fr(k,1,n) add(f[i][k][0],S[k]);
		fr(k,1,n) add(f[i][k][0],1ll*f[i-1][k][1]*val[k]%mod);
		// fr(j,1,n){
		// 	fr(k,j+1,n) add(f[i][k][1],1ll*f[i-1][j][1]*val[k]%mod);
		// 	add(f[i][j][0],1ll*f[i-1][j][1]*val[j]%mod);
		// 	fr(k,j+1,n) add(f[i][k][1],1ll*f[i-1][j][0]*j%mod*val[k]%mod);
		// 	// add(f[i][j][0],1ll*f[i-1][j][0]*val[j]%mod);
		// 	fr(k,1,j) add(f[i][k][1],1ll*f[i-1][j][0]*val[j]%mod*(k-1)%mod);
		// 	fr(k,1,j) add(f[i][k][0],1ll*f[i-1][j][0]*val[j]%mod);
		// }
	}
	// fr(i,1,n) fr(j,1,n) fr(k,0,1) cout<<i<<' '<<j<<' '<<k<<' '<<f[i][j][k]<<endl;
	int ans=0;
	fr(i,1,n){
		add(ans,f[n][i][1]);
		add(ans,1ll*f[n][i][0]*i%mod);
	}
	writeln(ans);
}
inline void init(){
    while(cin>>n) work();
}
signed main(){
	// freopen("input.in","r",stdin);
	// freopen("output.out","w",stdout);
	init();
    // printf("\nTIME:%.3lf",(double)clock()/CLOCKS_PER_SEC);
	return 0;
}
/*
5
1 10 100 1000 10000
*/