#include <bits/stdc++.h>
using namespace std;

#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define FOR(i, a, b) for (int i = (a); i<(b); ++i)
#define RFOR(i, b, a) for (int i = (b)-1; i>=(a); --i)
#define MP make_pair
#define PB push_back
#define F first
#define S second
#define FILL(a, b) memset(a, b, sizeof(a))

typedef long long LL;
typedef pair<int, int> PII;
typedef vector<int> VI;

const int N = 1 << 17;
VI vecs[N];
int u[N];

void solve(){
	int n;
	cin >> n;
	FOR(i, 1, n + 1){
		vecs[i].clear();
		u[i] = 0;
	}
	FOR(p, 3, n + 1){
		if(u[p] || p % 2 == 0)
			continue;
		vecs[p].PB(p);
		for(int j = 3 * p; j <= n; j += p)
			if(!u[j]){
				vecs[p].PB(j);
				u[j] = 1;
			}
	}
	int ans = 0;
	FOR(p, 3, n + 1){
		if(SZ(vecs[p]) % 2){
			if(2 * p <= n){
				vecs[p].PB(2 * p);
				u[2 * p] = 1;
			}
			else
				vecs[p].pop_back();
		}
		ans += SZ(vecs[p]) / 2;
	}
	FOR(i, 1, n + 1)
		if((i % 2 == 0) && !u[i])
			vecs[2].PB(i);
	if(SZ(vecs[2]) % 2)
		vecs[2].pop_back();
		
	ans += SZ(vecs[2]) / 2;
	
	cout << ans;
	FOR(p, 1, n + 1){
		for(int i : vecs[p])
			cout << " " << i;
	}
	cout << "\n";

}


int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	
	int t;
	cin >> t;
	while(t--)
		solve();
	
	
	return 0;
}