/*** author: yuji9511 ***/ #include // #include // using namespace atcoder; using namespace std; using ll = long long; using lpair = pair; using vll = vector; 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 void print(H&& h, T&&... t){cout<(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(); }