# import sys; input = sys.stdin.buffer.readline
# sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

#処理内容
def main():
	T = int(input())
	for x in range(T):
		N = int(input())
		A = getlist()
		DPleft = [[INF] * (N + 2) for i in range(N + 1)]
		DPright = [[INF] * (N + 2) for i in range(N + 1)]
		DPleft[0][0] = -INF
		DPright[-1][0] = -INF; DPright[-1][1] = A[-1]
		for i in range(N):
			for j in range(N + 1):
				DPleft[i + 1][j] = min(DPleft[i + 1][j], DPleft[i][j])
				if A[i] - DPleft[i][j] >= j:
					DPleft[i + 1][j + 1] = min(DPleft[i + 1][j + 1], A[i])
		
		for i in range(N - 1, -1, -1):
			for j in range(N + 1):
				DPright[i][j] = min(DPright[i + 1][j], DPright[i][j])
				if A[i - 1] - DPright[i + 1][j] >= j:
					DPright[i][j + 1] = min(DPright[i][j + 1], A[i - 1])


		# print(DPleft)
		# print(DPright)
		ans = 1
		for i in range(1, N):
			left = 0
			right = 0
			for j in range(1, N + 1):
				if DPleft[i - 1][j] + j <= A[i - 1]:
					left = j
				if DPright[i + 1][j] + j <= A[i - 1]:
					right = j

			# print(left, right)

			ans = max(ans, left + right + 1)

		print(ans)

if __name__ == '__main__':
	main()