## Learn Python with Challenges

Solve challenges and become a Python expert.

A Fibonacci sequence is the integer sequence of 0, 1, 1, 2, 3, 5, 8....

The first two terms are 0 and 1. All other terms are obtained by adding the preceding two terms. This means to say the nth term is the sum of (n-1)th and (n-2)th term.

## Source Code

```
# Program to display the Fibonacci sequence up to n-th term
nterms = int(input("How many terms? "))
# first two terms
n1, n2 = 0, 1
count = 0
# check if the number of terms is valid
if nterms <= 0:
print("Please enter a positive integer")
# if there is only one term, return n1
elif nterms == 1:
print("Fibonacci sequence upto",nterms,":")
print(n1)
# generate fibonacci sequence
else:
print("Fibonacci sequence:")
while count < nterms:
print(n1)
nth = n1 + n2
# update values
n1 = n2
n2 = nth
count += 1
```

**Output**

How many terms? 7 Fibonacci sequence: 0 1 1 2 3 5 8

Here, we store the number of terms in `nterms`. We initialize the first term to 0 and the second term to 1.

If the number of terms is more than 2, we use a `while`

loop to find the next term in the sequence by adding the preceding two terms. We then interchange the variables (update it) and continue on with the process.

You can also solve this problem using recursion: Python program to print the Fibonacci sequence using recursion.