#include <bits/stdc++.h>
using namespace std;
#define FINISH cerr << "FINISH" << endl;
#define int long long
#define debug(x) cerr << #x << " == " << x << endl
#define el '\n'
#define fir first
#define sec second
typedef long long ll;
typedef pair<int, int> PII;
const int mod = 998244353;
const int inf = 0x3f3f3f3f;
const int N = 200020;
ll ksm(ll a, ll b)
{
	ll sum = 1;
	while (b) {
		if (b & 1)
			sum = sum * a % mod;
		a = a * a % mod;
		b >>= 1;
	}
	return sum;
}
ll inv(ll x)
{
	return ksm(x, mod - 2);
}
void solve()
{
	int n, res = 1, tot;
	cin >> n;
	vector<int> a(n + 1, 0), b(n + 1), siz(n + 1, 0), sum(n + 1, 0);
	a[1] = 1;
	for (int i = 1; i <= n; i++) {
		cin >> b[i];
		if (i >= 2) {
			if (b[i] == b[i - 1])
				a[i] = a[i - 1];
			else
				a[i] = a[i - 1] + 1;
		}
		sum[a[i]]++;
		siz[a[i]]++;
	}
	tot = a[n];
	if (tot < n / 2) {
		cout << "0" << endl;
		return;
	}
	for (int i = 1; i <= n; i++) {
		sum[i] += sum[i - 1];
	}
	/*cout << "SUM::" << endl;
	for (int i = 1; i <= n; i++) {
		cout << sum[i] << " ";
	}
	cout << endl;*/
	function<ll(ll)> up = [&](ll x) { return (x % mod + mod) % mod; };
	vector<vector<ll>> dp(n + 1, vector<ll>(n + 1, 0));
	for (int i = 1; i <= tot; i++) {
		dp[1][i] = sum[i - 1];
	}
	for (int i = 2; i <= n / 2; i++) {
		vector<ll> ss(n + 1, 0);
		// debug(i);
		for (int j = 1; j <= tot; j++) {
			// cout << j << " " << sum[j - 1] - 2 * i + 3 << endl;
			if (sum[j - 1] - 2 * i + 3 <= 0) {
				ss[j] = ss[j - 1];
			}
			else {
				// cout << "FIND " << j << " " << dp[i - 1][j] << endl;
				ss[j] =
					ss[j - 1] +
					(dp[i - 1][j] * (sum[j - 1] - 2 * i + 3) % mod) * siz[j];
				ss[j] = up(ss[j]);
			}
			// up(ss[j]);
			dp[i][j] = ss[j - 1];
		}
		/*cout << "SS:" << endl;
		for (int j = 1; j <= tot; j++) {
			cout << ss[j] << " ";
		}
		cout << endl;*/
	}
	/*for (int i = 1; i <= n / 2; i++) {
		debug(i);
		for (int j = 1; j <= tot; j++) {
			cout << dp[i][j] << " ";
		}
		cout << endl;
	}*/
	ll ans = dp[n / 2][tot];
	for (int i = 1; i <= tot; i++) {
		for (int j = 1; j <= siz[i]; j++) {
			ans = ans * inv(j);
			ans = up(ans);
		}
	}
	cout << ans << endl;
}
signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	int T = 1;
	cin >> T;
	while (T--) {
		solve();
	}
	return 0;
}