JavaScript Program to Display Fibonacci Sequence Using Recursion

To understand this example, you should have the knowledge of the following JavaScript programming topics:

• JavaScript Recursion

A fibonacci sequence is written as:

              

0, 1, 1, 2, 3, 5, 8, 13, 21, ...

            

The Fibonacci sequence is the integer sequence where the first two terms are 0 and 1. After that, the next term is defined as the sum of the previous two terms. Hence, the nth term is the sum of (n-1)th term and (n-2)th term.

Example: Fibonacci Sequence Upto nth Term using Recursion

              

// program to display fibonacci sequence using recursion
function fibonacci(num) {
    if(num < 2) {
        return num;
    }
    else {
        return fibonacci(num-1) + fibonacci(num - 2);
    }
}

// take nth term input from the user
const nTerms = prompt('Enter the number of terms: ');

if(nTerms <=0) {
    console.log('Enter a positive integer.');
}
else {
    for(let i = 0; i < nTerms; i++) {
        console.log(fibonacci(i));
    }
}

            

Output

              

Enter the number of terms: 5
0
1
1
2
3

            

In the above program, a recursive function fibonacci() is used to find the fibonacci sequence.

• The user is prompted to enter a number of terms up to which they want to print the Fibonacci sequence(here 5).
• The if…else statement is used to check if the number is greater than 0.
• If the number is greater than 0, a for loop is used to calculate each term recursively (calls the fibonacci() function again).

Also Read:

• JavaScript Program to Print the Fibonacci Sequence