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 A306927 a(n) = A001615(n) - n. 2
 0, 1, 1, 2, 1, 6, 1, 4, 3, 8, 1, 12, 1, 10, 9, 8, 1, 18, 1, 16, 11, 14, 1, 24, 5, 16, 9, 20, 1, 42, 1, 16, 15, 20, 13, 36, 1, 22, 17, 32, 1, 54, 1, 28, 27, 26, 1, 48, 7, 40, 21, 32, 1, 54, 17, 40, 23, 32, 1, 84, 1, 34, 33, 32, 19, 78, 1, 40, 27, 74, 1, 72 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Analogous to A051953. a(n) = A051953(n) if n is an element of A000961. a(n) > A051953(n) if n is an element of A024619. The sum of the proper divisors d of n such that n/d is squarefree. - Amiram Eldar, Sep 06 2019 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 Wikipedia, Dedekind psi function FORMULA a(n) = A001615(n) - n. a(n) = Sum_{d|n, d

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Last modified February 25 06:46 EST 2020. Contains 332220 sequences. (Running on oeis4.)