#!/usr/bin/ruby
#
## https://rosettacode.org/wiki/Left_factorials#Sidef
#
func left_fact(k) {
    sum(^k, { _! })
}
[range(0, 10), range(20, 50).by(10)].each { |r|
    r.each { |i|
        printf("!%d  = %s\n", i, left_fact(i));
    }
}