The Fibonacci numbers F(n) are as follows:
F(0) = 0,
F(1) = 1,
F(2) = 1,
and all further values of F(n) are defined by the simple recurrence
F(n) =
F(n − 1) + F(n − 2).
The Fibonacci sequence is quite famous; it is sequence
A000045 in the
Online Encyclopedia of Integer Sequences,
where you can find lots of additional information.
Many authors omit the zeroth term F(0) = 0, and so
the Fibonacci series is often considered starting with the term F(1) = 1.
The values F(n) appear as diagonal sums of
binomial coefficients in
Pascal's triangle.
This online calculator computes the Fibonacci numbers F(n)
for input values 0 ≤ n ≤ 50000 in arbitrary precision arithmetic.
So, for example, you will get all 418 digits of F(2000) –
a very large number!
See also:
• 100+ digit calculator: arbitrary precision arithmetic
• Prime factorization calculator
• Binomial coefficients calculator
• Euler's totient function φ calculator
• Highly composite numbers
• Divisors and sumofdivisors calculator
• Catalan numbers calculator

