Fibonacci?

Leonardo Fibonacci 1170-1248 was one of the most influential mathematicians of the Middle Ages. He was born in Pisa; now in Northern Italy but then the independent Republic of Pisa.

It was Fibonacci who popularized the use of Indian Vedic number notation; 0, 1, 2, 3, etc. instead of Roman numerals I, II, III, IV, etc.

Especially, Fibonacci made the zero notation 0 acceptable in European mathematics.

The Fibonacci series of numbers is formed from the relation n₃ = n₂ + n₁

So, starting with 1, the series is

1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377 etc.

For some reason, modern descriptions start with zero: 0, 1, 1, 2, etc.

This sequence has been used to describe various natural phenomena such as the breeding-population of insects, numbers of leaves on trees, and also search algorithmic processes in computer science.

Although Fibonacci's book "Liber Abaci" [Calculating Book] contains the earliest known description of the sequence in Europe, it was known and used by Indian mathematicians in the sixth century. It is assumed that he found it in documents arriving in Venice, Genoa and Pisa from India as a result of the Islamic invasion of Europe.

By the way, his name is pronounced Fee-bo-NATCH-ee.

Fibonacci are numbers that are an example of a complete sequence. This means that every positive integer can be written as a sum of Fibonacci numbers, where any one number is used once at most.

Fibonacci numbers: 1,1,2,3,5,8,13,.. To get the next number, add the two previous numbers: 5+8=13.