#!/usr/bin/perl -w
# Password use of the last 4 digits of your socail security number, so 
# there are 10,000 possibilities.
# In a group of N people, what is the likelihood that the last four 
# digits of their social security number are the same?

$p = 1;		# probability
$N=150;		# population size
for ($J=1; $J < $N; $J++) {
	$p =$p*(1 - $J/9999);
	$j = $J+1;
	if (($j % 10) == 0) {$P=1-$p; print "  $j   $P\n";}
}

