# import pypyjit
# pypyjit.set_param('max_unroll_recursion=-1')
from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
input = sys.stdin.readline


x = 1/(math.e*math.pi*math.pi)

def g(t,N):
    return math.exp(math.cos(t/N))
    
def f(N):
    S = g(0,N)+g(x,N)
    
    for i in range(1,64):
        S += g(x*i/64,N)*2
    return x*S/128

for _ in range(int(input())):
    print(f(int(input())))