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Fibonacci Calculator - Fibonacci Sequence

Free Fibonacci calculator. Find any Fibonacci number, generate sequences, and explore the golden ratio.

Calculate Fibonacci numbers

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Fibonacci Calculator

Calculate Fibonacci numbers where each number is the sum of the two preceding ones. Found throughout nature and mathematics.

F(n) = F(n-1) + F(n-2), where F(1) = 1, F(2) = 1

Sequence: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55... Ratio of consecutive terms approaches golden ratio φ ≈ 1.618034.

Where do Fibonacci numbers appear in nature?

Flower petals, pinecones, sunflower seeds, nautilus shells, tree branching - all follow Fibonacci patterns.

What is the golden ratio?

φ = (1 + √5) / 2 ≈ 1.618. As n increases, F(n)/F(n-1) approaches φ. It appears in art, architecture, and nature.

Factorial Calculator

Calculate factorials

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