#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pdd = pair<double, double>;
using pll = pair<ll, ll>;
using pli = pair<ll, int>;
using pil = pair<int, ll>;
template <typename T>
using Graph = vector<vector<T>>;
const int MOD = 1e9 + 7;
const ld PI = acos(-1);

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    vector<ld> v(3001);
    ld ma = exp(1) * PI * PI;
    int lp = 2000;
    for (int i = 1; i < 3000; ++i) {
        for (int j = 0; j < lp; ++j) {
            ld now = j / ma / lp;
            ld nxt = (j + 1) / ma / lp;
            now = exp(cos(now / i));
            nxt = exp(cos(nxt / i));
            ld tmp = (now + nxt) / 2 / lp / ma;
            v[i] += tmp;
        }
    }
    v[3000] = 1 / PI / PI;

    cout << fixed << setprecision(15);

    int T;
    cin >> T;
    while (T--) {
        int N;
        cin >> N;
        cout << v[min(N, 3000)] << "\n";
    }

    return 0;
}