Leonardo da Pisa, son of Gugliemo Bonacci ("figlio di Bonacci"), author of Liber Abaci, is today best known for a sequence of integers pertaining to the golden ratio.
The Fibonacci numbers are F(0) = 0, F(1) = 1, and for integers n greater than 1, F(n) = F(n − 2) + F(n − 1). The first few are 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144.
The Fibonacci numbers are easily extended to negative integer indices (example on Wolfram Alpha
) and with a little more effort, to other real numbers (example on Wolfram Alpha), imaginary numbers and complex numbers.
In movies and TV shows, we're only likely to see a few Fibonacci numbers for very small positive indices. For example in the Family Guy episode "Baby Stewie", Stewie tells Brian the answer to the escape room riddle is the Fibonacci sequence from The Da Vinci Code. Brian then relays the answer to the rest of his family as if he figured it out himself, saying it's from an "Italian number guy."
In Sloane's On-Line Encyclopedia of Integer Sequences (OEIS), the Fibonacci numbers are listed at entry A45. There's also a scholarly journal, the Fibonacci Quarterly (often abbreviated Fib. Quart.), expressly devoted to the study of Fibonacci numbers.
