# Python Program for Sum of Squares of first n natural numbers

Hello coders, in this tutorial we are going to discuss and write the code for the sum of squares of first n natural numbers using Python. Firstly, we will see the proof then we will proceed with the coding part.

## Sum of the square of first n natural number using Python

Given a positive integer n., The task is to find 1^{2} + 2^{2} + 3^{2} + ….. + n^{2}

Now let’s see our program to perform the task.

**For example:-**

Input : n = 5 Output : 30 1 + 4 + 9 + 16 +25= 55 Input : n = 6 Output : 91

Technique 1:-

#Using Method 1 def squaresum(n) : s = 0 #Iteration from 1 to n for i in range(1, n+1) : s = s + (i * i) return s n = 5 print(squaresum(n))

Output:- 55

Method 2:-

Using the formula

Sum of square of first n natural numbers = (n*(n+1)*(2*n+1))/6

Example:-

When n=4

Then, sum=(4*5*9)/6

sum=30

Code for technique 2:-

#Using Method 2 def squaresum(n) : return (n * (n + 1) * (2 * n + 1)) // 6 n = 4 print(squaresum(n))

Output:- 30

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