title: algorithm to count cows in farm ( js or any language)
body: <p>i need to count number of cows in farm, starting from this year (2017)  to year at the end (2057), fi in this farm is 1 cow, witch born cows , after 4 years this cows born his own cows so on... every calf can born 1 calf every ear, and no one dies in this farm. How to count number of cows?</p>