Ontario Mathematics Olympiad

Sample Question #4

Leonardo Pisano Fibonacci 12^th Century Italy

A certain man put a pair of rabbits in a place surrounded on all sides by a wall. How many rabbits can be produced from that pair in a year, if it is supposed that every month each pair of rabbits begets a new pair that from the second month on becomes productive?

Start with: 1, 1, 2, 3, ...