[seqfan] Re: Wrong formula in A091050

[israel at math.ubc.ca]

The author of that formula seems to have forgotten that there could be 
perfect powers divisible by more than one prime. I think any "repair" would 
have very little resemblance to the current formula. My suggestion would be 
to delete.

Cheers,
Robert

On Apr 28 2020, Ami Eldar wrote:

>Dear SeqFans,
>
>The first formula in A091050 (Number of divisors of n that are perfect
>powers.) is wrong:
>a(n) = A073093(n)-A001221(n) = A001222(n)-A001221(n)+1.
>(the 2nd equals sign is correct).
>
>This formula is wrong for the values of n = 36, 72, 100, 108, 144, 180,...
>E.g. 36 has 4 divisors that are perfect powers 1, 4, 9, 36,
>yet A001222(36)-A001221(36)+1 = 4 - 2 + 1 = 3.
>
>My question is whether this formula is repairable, or should it be deleted?
>
>Thanks,
>Amiram
>
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>
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