N rabbits in a bag - numerical solution

puzzle.py

"""
A numeric solution for a probability question I thought about, 
It's similar to a "n marbles in a bag" type question: If I had
some rabbits that grow year by year, and every year I chose one
rabbit at random, noted its age and replaced it with a baby)
so out of N integers (each rabbits age), one of them gets swapped
with zero and then they all grow by one. What's the average age
of the rabbits i'm pulling out?
"""

from random import randint
from math import log10

n = 30
loops = int(10**7)

rabbits = [0]*n
average = 0
for i in range(loops):
	rabbits = [x+1 for x in rabbits]
	index = randint(0, n-1)
	average += rabbits[index]
	rabbits[index] = 0
	if i % int(loops/100) == 0:
		cur = average/(i+1)
		print(f"{i}/{loops} ({int(100*i/loops)}%) => average={cur:.2f}, distance from expected value=10e{log10(abs(n-cur)):.2f}")

average /= loops
print(f"average age={average} (expected {n})")