#include <stdio.h>

unsigned long int factorial(unsigned int n){
  if (n == 0)
    return 1;
  else return n * factorial(n - 1);
}

int main(void) {
  unsigned int k;

  // Upper limits of k:  12  (if long is 4 bytes)
  // Upper limits of k:  20  (if long is 8 bytes)

  for (k = 0; k <= 12; k++)                     
    printf("%-20lu %20lu\n", k, factorial(k));
  
  return 0;
}