Arithmetic & Number Theory

Lucas Number

The nth Lucas number (L₀=2, L₁=1).

Formula

Formula
Ln = Ln−1 + Ln−2

Variables

SymbolDefinitionType & rangeUnitsRole
n index integer (ℤ) input
Lₙ n-th Lucas number computed result result

Try it yourself

Interactive calculator
Result

Worked examples

Example 1
Givenn = 10
Result123
Example 2
Givenn = 15
Result1364