In this post, we will see how to print first n odd natural numbers in python?

Odd Numbers:

Any integer that is positive or negative which can not be divided exactly by 2 is an odd number. The numbers having the last digit is 1, 3, 5, 7 or 9 are odd numbers.

Note: Natural number is positive integers. It’s range from 1 to infinity.

Examples:

Input: n: 5

Output: 5 first odd natural numbers are: 1 3 5 7 9

Input: n: 6

Output: 6 first odd natural numbers are: 1 3 5 7 9 11

Let’s see the different version of codes for this program :

Code version 1: Using a counter.

In this code, we take a counter variable ‘odd’ initialized by 1 and on every iteration, this counter value is incremented by 2.

# main code
if __name__ == "__main__" :

    # input value of n
    n = 11

    # take a odd variable
    # and assign 1 to it
    odd = 1
    print("odd numbers are: ")
    # loop run from 0
    # to n - 1
    for i in range(n) :

        # print value of odd variable
        # and end parameter is ','
        # so print all outputs
        # in a single line with ','
        print(odd, end = ",")

        # increment by 2
        # in every iteration
        odd += 2

Output: odd numbers are: 

1,3,5,7,9,11,13,15,17,19,21,

Code version 2: Using an if-else statement along with for loop.

In this code, we run a loop from 1 to 2 * n – 1, and in every iteration, we check the value of i is divisible by 2 or not if not divisible then it is odd otherwise even.

# main code
if __name__ == "__main__" :

    # input value of n
    n = 7
    
    print("odd numbers are: ")
    # loop run from 1
    # to 2 * n - 1
    for i in range(1, 2 * n) :

        # if condition is True 
        # that means i % 2 gives 
        # non-zero value then 
        if i % 2 :
            
            # print value of i variable
            # and end parameter is ','
            # so print all outputs
            # in a single line with ','
            print(i, end = ",")

Output: odd numbers are: 

1,3,5,7,9,11,13,

Note : Code version 1 and 2 can also be written using While loop.

Code version 3: Using a range() function concept.

As we know, we can pass 3 parameters in range() function, the third parameter is stepped i.e jump after each iteration.

# main code
if __name__ == "__main__" :

    # input value of n
    n = 7

    print("odd numbers are: ")
    # loop run from 1
    # to 2 * n - 1
    for even in range(1, 2 * n, 2) :

        # print value of odd variable
        # and end parameter is ','
        # so print all outputs
        # in a single line with ','
        print(odd, end = ",")

Output: odd numbers are: 

1,3,5,7,9,11,13,