A python implementation of the ackermann function from here: http://www.eprg.org/computerphile/ackermann.c

ack.py

#!/usr/bin/python3

import sys
sys.setrecursionlimit(100000) #Python seems to be a sissy language by default.

def ack(m, n):
	if m == 0:
		ans = n + 1
	elif n == 0:
		ans = ack(m - 1, 1)
	else:
		ans = ack(m - 1, ack(m, n - 1))

	return ans

def main ():
	for i in range(0, 6):
		for j in range(0, 6):
			ackerman = "Ackerman ({},{}) is: {}".format(i, j, ack(i, j))
			print(ackerman)

main()

output

$ ./ack.py
Ackerman (0,0) is: 1
Ackerman (0,1) is: 2
Ackerman (0,2) is: 3
Ackerman (0,3) is: 4
Ackerman (0,4) is: 5
Ackerman (0,5) is: 6
Ackerman (1,0) is: 2
Ackerman (1,1) is: 3
Ackerman (1,2) is: 4
Ackerman (1,3) is: 5
Ackerman (1,4) is: 6
Ackerman (1,5) is: 7
Ackerman (2,0) is: 3
Ackerman (2,1) is: 5
Ackerman (2,2) is: 7
Ackerman (2,3) is: 9
Ackerman (2,4) is: 11
Ackerman (2,5) is: 13
Ackerman (3,0) is: 5
Ackerman (3,1) is: 13
Ackerman (3,2) is: 29
Ackerman (3,3) is: 61
Ackerman (3,4) is: 125
Ackerman (3,5) is: 253
Ackerman (4,0) is: 13
Segmentation fault (core dumped)

Apparently python does everything in it's power to make me not use recursion. At least like this.