1 #include <iostream>
 2 #include <stdio.h>
 3 #include <cmath>
 4 #include <vector>
 5 #include <algorithm>
 6 #include <set>
 7 #include <map>
 8 #include <queue>
 9 #include <deque>
10 #include <stack>
11 #include <string>
12 #include <bitset>
13 #include <ctime>
14 #include<algorithm>
15 #include<cstring>
16 using namespace std;
17 typedef long long ll;
18 int n;
19 const int maxn=1e6+2;
20 int a[maxn];
21 int ans;
22 int AP()
23 {
24     int l=0;
25     int r=1;
26     int add=a[r]-a[l];
27     int res=2;
28     while(l<n && r<n)
29     {
30         while(r<n && a[r]-a[r-1]==add)
31         {
32             r++;
33         }
34         res=max(res,r-l);
35         l=r-1;
36         add=a[r]-a[l];
37     }
38     return res;
39 }
40 int GP()
41 {
42     int l=0;
43     int r=1;
44     double q=(double)a[r]/(double)a[l];
45     int res=0;
46     while(l<n && r<n)
47     {
48         while(r<n && (double)a[r]/(double)a[r-1]==q)
49         {
50             r++;
51         }
52         res=max(res,r-l);
53         l=r-1;
54         q=(double)a[r]/(double)a[l];
55     }
56     return res;
57 }
58 int main()
59 {
60     int T;
61     scanf("%d",&T);
62     while(T--)
63     {
64         scanf("%d",&n);
65         for(int i=0;i<n;i++)
66         {
67             scanf("%d",&a[i]);
68         }    
69         if(n<=2)
70         {
71             printf("%d\n",n);
72             continue;
73         }
74         ans=2;
75         ans=max(ans,AP());
76         ans=max(ans,GP());
77         printf("%d\n",ans);
78     }
79     return 0;
80  }