/*** author: yuji9511 ***/
#include <bits/stdc++.h>
// #include <atcoder/all>
// using namespace atcoder;
using namespace std;
using ll = long long;
using lpair = pair<ll, ll>;
using vll = vector<ll>;
const ll MOD = 1e9+7;
const ll INF = 1e18;
#define rep(i,m,n) for(ll i=(m);i<(n);i++)
#define rrep(i,m,n) for(ll i=(m);i>=(n);i--)
ostream& operator<<(ostream& os, lpair& h){ os << "(" << h.first << ", " << h.second << ")"; return os;}
#define printa(x,n) for(ll i=0;i<n;i++){cout<<(x[i])<<" \n"[i==n-1];};
void print() {}
template <class H,class... T>
void print(H&& h, T&&... t){cout<<h<<" \n"[sizeof...(t)==0];print(forward<T>(t)...);}

void solve(){
    ll N;
    cin >> N;
    vll a(N);
    rep(i,0,N) cin >> a[i];
    ll ans = 0;
    ll cur = a[0];
    rep(i,1,N){
        cur = cur + a[i] + cur * a[i];
    }
    print(cur);

}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll t;
    cin >> t;
    while(t--) solve();
}