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A Quickie, not tricky (Posted on 2015-05-11)

How many ordered sets of positive integers are there if:

1.Their sum is less than 6
2. There are at most 4 addends
3. None of them is composite.

Please specify how quick were you to get the right answer.

No Solution Yet Submitted by Ady TZIDON

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Solution spoiler

| Comment 1 of 7

seven

1,2

1,3

2,3

Time: a few seconds to wonder if a set with one member should count.

I'm now wondering if ordered means

2,1

3,1

3,2

Should also count. That always confuses me.

Posted by Jer on 2015-05-11 09:41:43

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