[seqfan] Wrong formula in A091050
Ami Eldar
amiram.eldar at gmail.com
Tue Apr 28 17:55:31 CEST 2020
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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