Question

Sheldon Cooper’s (of Big Bang Theory) favorite number is 73. One of his reasons is that 73 is a prime number and there are 21 prime numbers between 1 and 73. A prime number is a number greater than 1 that is not divisible by another number (the only even number that is a prime number is 2; all other prime numbers are odd). Write the Python code to calculate and print the prime numbers between 1 and 73 (but not including 73). Your program will also need to count the prime numbers to see if this is really the 21th prime number.

Answer 1

Answer:

Following is the code as required:

print("2 is the level 1 prime number")

prime_count=1

end=73

for i in range(3,end):    

not_prime=0

for j in range(2,i):    

if(i%j==0):    

not_prime=not_prime+1

break    

if(not_prime==0):

prime_count=prime_count+1

print("",i" is the level ", prime_count," prime number)

print()

print(" Total number of prime numbers between 1, 73 is ",prime_count,"")  

Explanation:

• First of all 2 will be listed as the first prime number between 1 and 73.
• Total number of prime numbers will be stored in the variable prime_count.
• end variable will declare the upper bound as 73.
• First for loop having range from 3 to 73 will simply take each integer and send it to the second for loop to check for prime number.
• Second for loop having range from 2 to the integer i (lower bound of first loop) will check for prime numbers by dividing each integer "i" with that of "j", checking that it divides completely (giving remainder 0) or not.
• If the number "i" will not a prime number (if remainder = 0), it will increase the variable not_prime = 0 by 1 each time.
• When "i" will be a prime number it will make prime_count increase by 1 each time.
• print statement will be used to display each prime number with its level/rank.
• Total number of prime numbers between 1 and 73 will be given by the variable prime_count.