[seqfan] Re: Wrong formula in A091050
israel at math.ubc.ca
israel at math.ubc.ca
Tue Apr 28 19:32:51 CEST 2020
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
>
>--
>Seqfan Mailing list - http://list.seqfan.eu/
>
>
More information about the SeqFan
mailing list