Question

How to calculate sum of series 1 + 11 + 111 + 1111 + ... N in Python

Answer 1

# sum = 1 + 11 + 111 + 1111 + ... N 

def sum_of_series(N) :
    summ = 0
    tmp = 1
    
    i = 0
    while (i < N) :
        print(tmp, end=" ")
        if (i < N - 1) :
            print("+", end=" ")
            summ += tmp
            tmp = (tmp * 10) + 1
        i += 1
    
    summ += tmp
    
    return summ
        
N = 6
summ = sum_of_series(N)

print("= " + str(summ))


   
    
'''
run:

1 + 11 + 111 + 1111 + 11111 + 111111 = 123456

'''

 

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