shithub: kwa

ref: 96c2be96e4beaac08d89af4dea8069d9ca1c4b09
dir: /test/t.randk/

{
	k = 2
	n = NF
	i = 1
	while ( i <= n ) {
		if ( rand() < k/n ) {
			print i
			k--
		}
		n--
		i++
	}
}