mod = 998244353
def solve():
  n = int(input())
  A = list(map(int, input().split()))
  Q = [0 for _ in range(n + 1)]
  U = [0 for _ in range(n + 5)]
  C = [[0 for _ in range(n + 1)] for _ in range(n + 1)]
  for i in range(1, n + 1):
    C[i] = C[i - 1][:]
    a = A[i - 1]
    if a == -1:
      continue
    Q[a] = i
    U[i] = 1
    for j in range(a):
      C[i][j] += 1
  dp = [[0 for _ in range(n + 10)] for _ in range(n + 1)]
  dp[0][0] = 1
  for i in range(1, n + 1):
    if Q[i] == 0:
      for j in range(i - 1, n + 1):
        r = j - i + 1 - C[i - 1][j]
        if r > 0:
          dp[i][j] = (dp[i][j] + dp[i - 1][j] * r) % mod
        if U[j + 1] == 0:
          dp[i][j + 1] = (dp[i][j + 1] + dp[i - 1][j]) % mod
        if U[j + 2] == 0:
          dp[i][j + 2] = (dp[i][j + 2] + dp[i - 1][j]) % mod
    else:
      j = Q[i]
      dp[i][j] = (dp[i][j] + dp[i - 1][j - 2] + dp[i - 1][j - 1]) % mod
      for k in range(j + 1, n + 1):
        dp[i][k] = (dp[i][k] + dp[i - 1][k]) % mod
  ans = 0
  for i in range(1, n + 1):
    ans = (ans + dp[n][i]) % mod
  print(ans)
  return

for _ in range(int(input())):
  solve()