Weird prime generator

• Time : $O(MAX_N * 10000)$
• Space : $O(MAX_N * 10000)$

#include <bits/stdc++.h>
using namespace std;
vector<long long> a{0,7}, g{0,1}, pre{0,1}, p, sum;
unordered_set<long long> us{1};
class WeirdPrimeGen
{
    static bool ok(long long x) {
        if(us.count(x)) return false;
        us.insert(x);
        for(int i = 2; i * i <= x; i++) {
            if(x % i) continue;
            return false;
        }
        return true;
    }
    static void calc(long long n) {
        if(a.size() > n) return;
        calc(n-1);
        a.push_back(a.back() + __gcd(n, a.back()));
        g.push_back(a.back() - a[a.size()-2]);
        pre.push_back(pre.back() + (g.back() == 1));
        if(ok(g.back())) p.push_back(g.back());
        if(g.back() != 1) {
            sum.push_back((sum.size() ? sum.back() : 0) + a.back() / n);
        }
    }
public:
    static long long countOnes(long long n) {
        calc(n);
        return pre[n];
    }
    static long long maxPn(long long n) {
        while(p.size() < n) {
            calc(a.size());
        }
        long long res = 0;
        for(int i = 0; i < n; i++) res = max(res, p[i]);
        return res;
    }
    static int anOverAverage(long long n) {
        while(sum.size() < n) {
            calc(a.size());
        }
        return sum[n-1] / n;
    }
};