stagger.rb

l = [1]

seen = {1 => nil}
	
5000.times \
{
	
	j = (0...l.size).min_by { |x| l[x] }
	x = l.delete_at(j)
	p(x)
	
	([x * 2] + ((x % 3 == 1 && ((x - 1) / 3).odd?) ? [(x - 1) / 3] : [])).each \
	{
		|z|
		next if (seen.member?(z))
		l << z
		seen[z] = nil
		p(z)
	}
}