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Python Exercises

Python: Compute the sum of first n given prime numbers

Python Basic - 1: Exercise-52 with Solution

Write a Python program to compute the sum of first n given prime numbers.

Input:
n ( n ≤ 10000). Input 0 to exit the program.

Pictorial Presentation:

Python: Compute the sum of first n given prime numbers

Sample Solution:

Python Code:

MAX = 105000
print("Input a number (n≤10000) to compute the sum:(0 to exit)") 
is_prime = [True for _ in range(MAX)]
is_prime[0] = is_prime[1] = False
for i in range(2, int(MAX ** (1 / 2)) + 1):
  if is_prime[i]:
    for j in range(i ** 2, MAX, i):
      is_prime[j] = False 
primes = [i for i in range(MAX) if is_prime[i]] 
while True:
  n = int(input())
  if not n:
    break
  print("Sum of first",n,"prime numbers:")
  print(sum(primes[:n]))

Sample Output:

Input a number (n≤10000) to compute the sum:(0 to exit)
 25
Sum of first 25 prime numbers:
1060

Flowchart:

Flowchart: Python - Compute the sum of first n given prime numbers

Python Code Editor:

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Previous: Write a Python program to find the difference between the largest integer and the smallest integer which are created by 8 numbers from 0 to 9. The number that can be rearranged shall start with 0 as in 00135668.
Next: Write a Python program that accept a even number (>=4, Goldbach number) from the user and create a combinations that express the given number as a sum of two prime numbers. Print the number of combinations.

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