DAY 73

Comment

It might help to continue the sequence for a few more terms.
You can check whether you have found the value of N by adding 5 to your number, then dividing by 2. The result should be your original number.

Answer

N is 5.

Readers' methods

Beryl Lambert, Northumberland:
It looked like the answer might be 6, but adding 5 then dividing by 2 gives a smaller number than 6.
So I tried 5, which does not give anything smaller (nor larger!).
So 5 is the answer.

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