local date = require "date"
-- prints all FRIDAY the 13TH dates between year 2000 and 2010
for i = 2000, 2010 do
        -- year jan 1
        x = date(i, 1, 1)
        -- from january to december
        for j = 1, 12 do
                -- set date to 13, check if friday
                if x:setmonth(j, 13):getweekday() == 6 then
                        print(x:fmt("%A, %B %d %Y"))
                end
        end
end