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A347230
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Möbius transform of A344695, gcd(sigma(n), psi(n)).
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3
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1, 2, 3, -2, 5, 6, 7, 2, -3, 10, 11, -6, 13, 14, 15, -2, 17, -6, 19, -10, 21, 22, 23, 6, -5, 26, 3, -14, 29, 30, 31, 2, 33, 34, 35, 6, 37, 38, 39, 10, 41, 42, 43, -22, -15, 46, 47, -6, -7, -10, 51, -26, 53, 6, 55, 14, 57, 58, 59, -30, 61, 62, -21, -2, 65, 66, 67, -34, 69, 70, 71, -6, 73, 74, -15, -38, 77, 78, 79
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OFFSET
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1,2
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COMMENTS
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Not multiplicative because A344695 isn't either. For example, a(4) = -2, a(27) = 3, but a(108) = -2 != -6.
The absolute values are not equal to A007947. The first n where abs(a(n)) != A007947(n) is at n=108, with a(108) = -2, while A007947(108) = 6.
The first n such that a(n) does not divide n are: 196, 216, 392, 432, 441, 588, etc.
The zeros occur at n = 288, 576, 1440, 2016, 2880, 3168, 3744, 4032, etc.
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LINKS
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FORMULA
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PROG
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(PARI)
A001615(n) = if(1==n, n, my(f=factor(n)); prod(i=1, #f~, f[i, 1]^f[i, 2] + f[i, 1]^(f[i, 2]-1))); \\ After code in A001615
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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