Python: Find the first n Fibonacci numbers

Python Programming Puzzles: Exercise-51 with Solution

Write a Python program to find the first n Fibonacci numbers.

Input: 10
Output:
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
Input: 15
Output:
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610]
Input: 50
Output:
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368, 75025, 121393, 196418, 317811, 514229, 832040, 1346269, 2178309, 3524578, 5702887, 9227465, 14930352, 24157817, 39088169, 63245986, 102334155, 165580141, 267914296, 433494437, 701408733, 1134903170, 1836311903, 2971215073, 4807526976, 7778742049, 12586269025]

Sample Solution-1:

Python Code:

def test(n):
    a = [1, 1]
    while len(a) < n: a += [sum(a[-2:])]
    return a[:n]
n = 10
print("\nFind the first",n,"Fibonacci numbers:")    
print(test(n))
n = 15
print("\nFind the first",n,"Fibonacci numbers:")    
print(test(n))
n = 50
print("\nFind the first",n,"Fibonacci numbers:")    
print(test(n))

Sample Output:

Find the first 10 Fibonacci numbers:
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55]

Find the first 15 Fibonacci numbers:
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610]

Find the first 50 Fibonacci numbers:
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368, 75025, 121393, 196418, 317811, 514229, 832040, 1346269, 2178309, 3524578, 5702887, 9227465, 14930352, 24157817, 39088169, 63245986, 102334155, 165580141, 267914296, 433494437, 701408733, 1134903170, 1836311903, 2971215073, 4807526976, 7778742049, 12586269025]

Flowchart:

Visualize Python code execution:

The following tool visualize what the computer is doing step-by-step as it executes the said program:

Sample Solution-2:

Python Code:

def test(n):
    result = [1, 1]
    while len(result) < n:
        result.append(result[-1] + result[-2])
    return result
n = 10
print("Find the first",n,"Fibonacci numbers:")    
print(test(n))
n = 15
print("\nFind the first",n,"Fibonacci numbers:")    
print(test(n))
n = 50
print("\nFind the first",n,"Fibonacci numbers:")    
print(test(n))

Sample Output:

Find the first 10 Fibonacci numbers:
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55]

Find the first 15 Fibonacci numbers:
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610]

Find the first 50 Fibonacci numbers:
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368, 75025, 121393, 196418, 317811, 514229, 832040, 1346269, 2178309, 3524578, 5702887, 9227465, 14930352, 24157817, 39088169, 63245986, 102334155, 165580141, 267914296, 433494437, 701408733, 1134903170, 1836311903, 2971215073, 4807526976, 7778742049, 12586269025]

Flowchart:

Visualize Python code execution:

The following tool visualize what the computer is doing step-by-step as it executes the said program:

Python Code Editor :

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