The Fibonacci Sequence Fibonacci numbers make up the Fibonacci sequence. This sequence of numbers have been around for nearly 800 years. The sequence was formed by a brilliant mathematician in Pisa. His name was Leonardo of Pisa. (See Figure I) Leonardo of Pisa nicked named himself Fibonacci. He was born in Pisa in 1170. He wrote many books relating to mathematics including his well known book: Liber Abaci (in English- "Book of Calculating"). In Liber Abaci, he introduced Arabic numerals (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) into Western Culture. "He was the most productive mathematician in all the Middle Ages." (2) He discovered what is now called the Fibonacci