Question

Find the sum of the first n composites that do not end in the digit 2. (n = 6 ⇒ 51) using python

Answer 1

code screenshot:

o/p:

code:

# importing the count for infinite loop
from itertools import count

# function will tell if the number is composite or not
def isComposite(num): 
  
    # Corner cases 
    if (num <= 1): 
        return False
    if (num <= 3): 
        return False
  
    # This is checked so that we can skip  
    # middle five numbers in below loop 
    if (num % 2 == 0 or num % 3 == 0): 
        return True
    i = 5
    while(i * i <= num): 
          
        if (num % i == 0 or num % (i + 2) == 0): 
            return True
        i = i + 6
          
    return False

# driver code

n = int(input('Enter the number of terms: '))

# initialize the counter
counter = n

# initializing the variable to hold the sum
sum_composite = 0

# for loop will execute till infinity until the break condition is interpreted
for num in count():

    # check if the number is composite or not
    if isComposite(num):

        # check if the number ends with 2 or not
        if num % 10 != 2:

            sum_composite += num

            # decrement the counter
            counter -= 1

    # if the counter becomes 0 break the loop
    if counter == 0:
        break

# display the sum
print('Sum of first {} composite numbers is: {}'.format(n, sum_composite))

For help please comment. Thank You