This is a script that will calculate the number of subsets possible in a set of a given size

gistfile1.rb

def fac(n, limit)
	if n == 1
		return 1
	end
	if n == limit
		return limit
	end
	return n * fac(n - 1, limit)
end

def calculate_combinations(setsize)
	combinations = 0
	setsize.times do |x|
		fac_value = (fac(setsize, setsize - x) / fac(x + 1, 1))
		#puts "#{x+1}: #{fac_value}"
		combinations += fac_value
	end
	return combinations
end

number_of_combinations = calculate_combinations(200)
puts "Number of combinations: #{number_of_combinations}"