from collections import defaultdict


def solve():
    N = int(input())
    A = list(map(int, input().split()))

    def f(xs):
        dp = [defaultdict(int) for _ in range(N)]

        res = [1] * N
        for i in range(N):
            for j in range(i+1):
                d = xs[i] - xs[j]
                if d <= 0: continue

                # A[j], A[i] の長さ 2 の数列からスタート
                dp[i][d] = max(dp[i][d], 2)

                # 前の結果から伸ばす
                for pd, plen in dp[j].items():
                    if pd < d:
                        dp[i][d] = max(dp[i][d], plen + 1)

                res[i] = max(res[i], dp[i][d])

        return res

    lefts = f(A)
    rights = f(A[::-1])[::-1]
    return max([a+b-1 for a, b in zip(lefts, rights)])


T = int(input())
for t in range(T):
    ans = solve()
    print(ans)