Lucas number L_n

L_n = φ^n + (1-φ)^n.
Created by
Renato Passos, Eng. de Software
Reviewed by
Renato Passos, Eng. de Software

Last updated: Apr 18, 2026

L_n
123

About this calculator

The Lucas Number Calculator is an online tool that allows you to calculate the nth Lucas number, denoted as L_n. The Lucas sequence is a numerical sequence similar to the Fibonacci sequence but with a different recurrence relation. It is defined by the formula L_n = φ^n + (1-φ)^n, where φ is the golden ratio, approximately equal to 1.618033988749895.

The formula used by the calculator is based on the mathematical definition of the Lucas sequence. The golden ratio φ is an irrational constant that naturally appears in many areas of mathematics and nature. The calculator uses this formula to compute the value of L_n for a given n. This allows users to quickly obtain the value of any Lucas number without having to perform tedious manual calculations.

The Lucas sequence has applications in various fields, including number theory, algebra, and geometry. It also appears in problems of combinatorics and in mathematical models of population growth. The calculator is useful for students, researchers, and professionals who need to work with the Lucas sequence in their studies or projects.

When using the calculator, it's essential to keep in mind that the value of L_n grows rapidly with increasing n. This means that for large values of n, the result may be too large to be displayed precisely. In this case, the calculator may return an approximation or a truncated value.

Frequently asked questions

What is the Lucas sequence?

The Lucas sequence is a numerical sequence defined by the formula L_n = φ^n + (1-φ)^n, where φ is the golden ratio.

What is the relationship between the Lucas sequence and the Fibonacci sequence?

The Lucas sequence is similar to the Fibonacci sequence but with a different recurrence relation.

What is the purpose of the Lucas number calculator?

The calculator is used to quickly compute the value of any Lucas number without having to perform tedious manual calculations.

What are the applications of the Lucas sequence?

The Lucas sequence has applications in number theory, algebra, geometry, combinatorics, and mathematical models of population growth.

How to handle large results?

For large values of n, the result may be too large to be displayed precisely. The calculator may return an approximation or a truncated value.

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