Rt，感觉是 conner case 的问题。

#include <bits/stdc++.h>
using namespace std;
const int N = 71, mod = 1e9 + 7;
int n, tmp, a[N], cnt[N], pw[N];
int dp[N][1 << 19];
int p[] = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67};
int main(){
	cin >> n;
	for(int i = 1; i <= n; i++){
		int x; scanf("%d", &x);
		tmp = x;
		if(!cnt[x])
			for(int j = 0; j < 19; j++){
				while(tmp % p[j] == 0){
					a[x] ^= (1 << j);
					tmp /= p[j];
				}
			}
		cnt[x]++;
	}
	for(int i = 0; i < N; i++)
		pw[i] = (i ? pw[i - 1] * 2 % mod : 1);
	dp[0][0] = 1;
	for(int i = 1; i < N; i++)
		for(int j = 0; j < (1 << 19); j++){
			if(!cnt[i])
				dp[i][j] = dp[i - 1][j];
			else
				dp[i][j] = 1ll * pw[cnt[i] - 1] * (dp[i - 1][j] + dp[i - 1][j ^ a[i]]) % mod;
		}
	cout << dp[N - 1][0] - 1;
	return 0;
}