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Based on threes! (Posted on 2019-04-09)

How many positive integers less than or equal to 100 cannot be written as the sum of distinct powers of 3?

No Solution Yet Submitted by Danish Ahmed Khan

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Counting solution.

| Comment 1 of 5

Easier to find those that can be written as distinct powers of 3.

From {1,3,9,27} choose all subsets except the empty set for 15 numbers.

Including 81 we choose all subsets of {1,3,9} for 8 more.

So 23 numbers can be written and 100-23=77 cannot.

Posted by Jer on 2019-04-09 16:00:16

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