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 where n is provided by the user # take input from the user nterms = int(input("How many terms? ")) # first two terms n1 = 0 n2 = 1 count = 2 # check if the number of terms is valid if nterms <= 0: print("Plese enter a positive integer") elif nterms == 1: print("Fibonacci sequence:") print(n1) else: print("Fibonacci sequence:") print(n1,",",n2,end=', ') while count < nterms: nth = n1 + n2 print(nth,end=' , ') # update values n1 = n2 n2 = nth count += 1
Output :
How many terms? 10 Fibonacci sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34,
Explanation
Here, we ask the user for the number of terms in the sequence. 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.