What is the Fibonacci sequence?
The Fibonacci sequence is a series of numbers in which each number is the sum of the two before it: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34 and so on.
The sequence is named after Leonardo of Pisa, known as Fibonacci, who described it in his 1202 book Liber Abaci using a puzzle about breeding rabbits. Indian mathematicians had described the same pattern centuries earlier in studies of poetry rhythms.
As the sequence continues, the ratio between neighboring numbers gets closer and closer to about 1.618, the golden ratio. For example, 34 ÷ 21 is about 1.619.
Fibonacci in nature
Fibonacci numbers appear in many plants. The number of petals on many flowers, and the spirals in sunflower heads, pine cones and pineapples, often match Fibonacci numbers. This arrangement helps plants pack seeds and leaves efficiently.
Fibonacci numbers are also used in computer science, for example in certain search methods and data structures, and in financial analysis, where some traders look for Fibonacci ratios in price charts.
Did You Know?
Fibonacci also helped spread Hindu-Arabic numerals, the digits 0 to 9 we use today, through Europe with the same book.