Problem 58013. Find a number m such that 2m and the square of m have the same digit sum

Created by ChrisR

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The number  has the property that  and  have the same digit sum. It is the seventh number, including zero, in the sequence of numbers with that property. 
Write a function to find the nth term in the sequence, where n can be a vector. 

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Last Solution submitted on Jul 28, 2025

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Christian Schröder on 23 Apr 2023

> It is the sixth number, including zero, in the sequence of numbers with that property.

Isn't it the seventh?

Also, out of curiosity, why are you disallowing persistent variables?

ChrisR on 23 Apr 2023

Yes, seventh--corrected, thanks. Bitten by the "off by one bug" again.

Banning persistent is to add the challenge of dealing with large numbers in Cody time. A while ago I found a quicker way to find the digit sums of a lot of numbers, and this problem was another place to exploit that method.

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Problem 58013. Find a number m such that 2m and the square of m have the same digit sum

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Problem 58013. Find a number m such that 2m and the square of m have the same digit sum

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Last 200 Solutions

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Problem Recent Solvers6

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