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#include <bits/stdc++.h>
#define MP make_pair
#define PB push_back
#define int long long
#define st first
#define nd second
#define rd third
#define FOR(i, a, b) for(int i =(a); i <=(b); ++i)
#define RE(i, n) FOR(i, 1, n)
#define FORD(i, a, b) for(int i = (a); i >= (b); --i)
#define REP(i, n) for(int i = 0;i <(n); ++i)
#define VAR(v, i) __typeof(i) v=(i)
#define FORE(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
#define __builtin_ctz __builtin_ctzll
#define __builtin_clz __builtin_clzll
#define __builtin_popcount __builtin_popcountll
using namespace std;
#ifdef LOCAL
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#define debugv(x) {{cerr <<#x <<" = "; FORE(itt, (x)) cerr <<*itt <<", "; cerr <<"\n"; }}
#else
#define debug(...) (__VA_ARGS__)
#define debugv(x)
#define cerr if(0)cout
#endif
#define next ____next
#define prev ____prev
#define left ____left
#define hash ____hash
typedef long long ll;
typedef long double LD;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<ll> VLL;
typedef vector<pair<int, int> > VPII;
typedef vector<pair<ll, ll> > VPLL;

template<class T> ostream& operator<<(ostream& out, vector<T> vec);
template<class T> ostream& operator<<(ostream& out, set<T> vec);
template<class L, class R> ostream& operator<<(ostream& out, map<L, R> vec);
template<class C> void mini(C&a4, C b4){a4=min(a4, b4); }
template<class C> void maxi(C&a4, C b4){a4=max(a4, b4); }
template<class T1, class T2>
ostream& operator<< (ostream &out, pair<T1, T2> pair) { return out << "(" << pair.first << ", " << pair.second << ")";}
template<class A, class B, class C> struct Triple { A first; B second; C third;
  bool operator<(const Triple& t) const { if (st != t.st) return st < t.st; if (nd != t.nd) return nd < t.nd; return rd < t.rd; } };
template<class T> void ResizeVec(T&, vector<int>) {}
template<class T> void ResizeVec(vector<T>& vec, vector<int> sz) {
  vec.resize(sz[0]); sz.erase(sz.begin()); if (sz.empty()) { return; }
  for (T& v : vec) { ResizeVec(v, sz); }
}
typedef Triple<int, int, int> TIII;
template<class A, class B, class C>
ostream& operator<< (ostream &out, Triple<A, B, C> t) { return out << "(" << t.st << ", " << t.nd << ", " << t.rd << ")"; }
template<class T> ostream& operator<<(ostream& out, vector<T> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }
template<class T> ostream& operator<<(ostream& out, set<T> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }
template<class L, class R> ostream& operator<<(ostream& out, map<L, R> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }
ostream& operator<<(ostream& out, __int128_t x) {
  if (x < 0) { out<<"-"; x = -x; }
  if (x == 0) { return out<<"0"; }
  VI digs;
  while (x) {
    digs.PB(x % 10);
    x /= 10;
  }
  reverse(ALL(digs));
  for (auto d : digs) { out<<d; }
  return out;
}
template<typename TH> void _dbg(const char* sdbg, TH h) { cerr<<sdbg<<"="<<h<<"\n"; }
template<typename TH, typename... TA> void _dbg(const char* sdbg, TH h, TA... t) {
  while(*sdbg != ',') { cerr<<*sdbg++; } cerr<<"="<<h<<","; _dbg(sdbg+1, t...);
}

const int P = 1e9 + 7;
int spow(int a, int b) {
  int r = 1;
  while (b) {
    if (b % 2) {
      r = r * a % P;
    }
    a = a * a % P;
    b /= 2;
  }
  return r;
}
const int N = 4e6 + 5;
int fact[N];
int pi2[N];

int f(int s, int d) {
  if (s < 0 || d < 0) { return 0; }
  return fact[s + 2 * d] * pi2[d] % P;
}

int g(int s, int set_cards, int n) {
  int cards = 4 * n - set_cards;
  assert ((s + cards) % 2 == 0);
  int d = (cards - s) / 2;
  return f(s, d);
}

int Choose2(int n) {
  return n * (n - 1) / 2 % P;
}
int Choose3(int n) {
  return (__int128_t)n * (n - 1) * (n - 2) / 6 % P;
}
int sum_ns;
struct Sol {
  void Test() {
    int n;
    cin>>n;
    sum_ns += n;
    int was_zero = 0, was_two = 0, was_one = 0;
    VI t;
    RE (i, 2 * n) {
      int x;
      cin>>x;
      t.PB(x);
      if (x == 0) { was_zero = 1; }
      if (x == 1) { was_one = 1; }
      if (x == 2) { was_two = 1; }
    }
    if (was_two && was_zero) {
      cout<<"0\n";
      return;
    }
    if (!was_two && !was_zero) {
      int res = (2 * n * n % P * (n - 1) % P * f(3, 2 * n - 3) % P + (2 * n * n % P * f(1, 2 * n - 2))) % P;
      cout<<res<<"\n";
      return;
    }
    if (!was_one) {
      int res = n * f(0, 2 * n - 1) + n * (n - 1) % P * f(2, 2 * n - 2);
      cout<<res % P<<"\n";
      return;
    }
    if (was_zero) {
      REP (i, 2 * n) {
        t[i] = 2 - t[i];
      }
      t.PB(t[0]);
      t.erase(t.begin());
    }
    //debug(t);
    int any = 0;
    REP (i, 2 * n - 1) {
      if (t[i] == 1 && t[i + 1] == 2) {
        any = i + 1;
        break;
      }
    }
    //debug(any);
    if (any % 2 == 1) {
      cout<<"0\n";
      return;
    }
    REP (j, any) {
      t.PB(t[j]);
    }
    //debug(t);
    t.erase(t.begin(), t.begin() + any);
    VI bloki;
    assert(t[0] == 2 && t.back() == 1);
    t.PB(2);
    int cur_blok = 1;
    REP (i, 2 * n) {
      if (t[i] != t[i + 1]) {
        bloki.PB(cur_blok);
        cur_blok = 1;
      } else {
        cur_blok++;
      }
    }
    assert(cur_blok == 1);
    //debug(bloki);
    for (auto blok : bloki) {
      if (blok % 2 == 0) {
        cout<<"0\n";
        return;
      }
    }
    int B = SZ(bloki);
    // najpierw blok dwojek, potem blok jedynek
    VI ones_blocks, twos_blocks;
    for (int i = 0; i < B; i++) {
      if (i % 2 == 0) {
        twos_blocks.PB(bloki[i]);
      } else {
        ones_blocks.PB(bloki[i]);
      }
    }
    assert(B % 2 == 0);
    int res = 0;
    int easy1 = 0, easy2 = 0;
    int hard1 = 0, hard2 = 0, hard3 = 0, hard4 = 0;
    for (auto blok : twos_blocks) { // bloki dwojek, liczymy AAPAPA
      int pos = (blok - 1) / 2;
      int here = Choose2(pos) * g(B + 2, B + 2, n) % P;
      res = (res + here) % P;
      easy1 = (easy1 + here) % P;
    }
    //debug(easy1);
    for (auto blok : ones_blocks) { // bloki jedynek, liczymy PPAPAPA
      int posP = (blok - 1) / 2;
      int here = Choose3(posP + 1) * g(B + 3, B + 3, n) % P;
      res = (res + here) % P;
      easy2 = (easy2 + here) % P;
    }
    //debug(easy2);
    for (auto blok : twos_blocks) {
      int set_as = B / 2;
      int fixed_intv = 2 * n - blok + 1;
      int free_as = fixed_intv / 2 - set_as;
      int here = set_as * g(B - 1, B + 1, n) % P + free_as * g(B + 1, B + 1, n);
      here %= P;
      res = (res + here) % P;
      hard1 = (hard1 + here) % P;
    }
    //debug(hard1);
    for (auto blok : ones_blocks) {
      int pairs_cnt = blok / 2;
      int choose_AP = Choose2(pairs_cnt + 1);
      int set_ps = B / 2;
      int fixed_intv = 2 * n - blok + 1;
      int free_ps = fixed_intv / 2 - set_ps;
      //debug(choose_AP, g(B + 1, B + 3, n), set_ps + 1);
      int place_app1 = choose_AP * g(B + 1, B + 3, n) % P * (set_ps + 1) % P; // wolne P sie naklada z jakims innym (byc moze tym ostatnim)
      int place_app2 = choose_AP * g(B + 3, B + 3, n) % P * free_ps % P; // wolne P sie nie naklada z nikim i jest w zafiksowanym przedziale
      int choose_APP = Choose3(pairs_cnt + 1);
      int place_app3 = choose_APP * g(B + 3, B + 3, n) % P; // w nieznanym przedziale mamy APP
      int place_app4 = place_app3; // w nieznanym przedziale mamy PAP
      //debug(place_app1, place_app2, place_app3, place_app4);
      int here = (place_app1 + place_app2 + place_app3 + place_app4) % P;
      res = (res + here) % P;
      hard2 = (hard2 + here) % P;
    }
    //debug(hard2);
    for (auto blok : twos_blocks) {
      int set_as = B / 2;
      int fixed_intv = 2 * n - blok + 1;
      int free_as = fixed_intv / 2 - set_as;
      int choose_A = blok / 2;
      int choose_AA = Choose2(blok / 2);
      int place_aa1 = choose_A * g(B, B + 2, n) % P * (set_as + 1) % P; // wolne A sie naklada z jakims innym
      int place_aa2 = choose_A * g(B + 2, B + 2, n) % P * free_as % P; // wolne A sie nie naklada z nikim i jest w zafiksowanym przedziale
      int place_aa3 = choose_AA * g(B + 2, B + 2, n) % P; // w nieznanym przedziale mamy AA;
      int here = (place_aa1 + place_aa2 + place_aa3) % P;
      res = (res + here) % P;
      hard3 = (hard3 + here) % P;
    }
    //debug(hard3);
    for (auto blok : ones_blocks) {
      int set_ps = B / 2;
      int fixed_intv = 2 * n - blok + 1;
      int free_ps = fixed_intv / 2 - set_ps;
      int pairs_cnt = blok / 2;
      int choose_A = pairs_cnt;
      int choose_PA = Choose2(pairs_cnt);
      int place_pa1 = choose_A * g(B, B + 2, n) % P * set_ps % P; // wolne P sie naklada z jakims innym
      int place_pa2 = choose_A * g(B + 2, B + 2, n) % P * free_ps % P; // wolne P sie nie naklada z nikim i jest w zafiksowanym przedziale
      int place_pa3 = choose_PA * g(B + 2, B + 2, n) % P; // w nieznanym przedziale mamy PA 
      int here = (place_pa1 + place_pa2 + place_pa3) % P;
      res = (res + here) % P;
      hard4 = (hard4 + here) % P;
    }
    //debug(hard4);
    cout<<res<<endl;
    //cerr<<"?\n";
  }
};



int32_t main() {

  ios_base::sync_with_stdio(0);
  cout << fixed << setprecision(10);
  cerr << fixed << setprecision(10);
  cin.tie(0);
  //double beg_clock = 1.0 * clock() / CLOCKS_PER_SEC;
  
  pi2[0] = 1;
  fact[0] = 1;
  int i2 = (P + 1) / 2;
  RE (i, N - 1) {
    fact[i] = i * fact[i - 1] % P;
    pi2[i] = pi2[i - 1] * i2 % P;
  }
  
  int t;
  cin>>t;
  RE (i, t) {
    Sol sol;
    sol.Test();
  }
  debug(sum_ns);

  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  return 0;
}