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Search: id:A066087
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| A066087 |
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Difference between GCD[Sigma(kernel of n),Phi(kernel of n)] and GCD[Sigma(n),Phi(n)]; kernel = A007947. |
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6
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| 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 2, -1, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 2, -2, 0, 0, 2, 1, -1, 0, -4, 0, 4, 0, 18, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, -4, -2, 0, 0, 0, 0, -1, 0, 0, -4, 0, 0, 0, 18, 0, -2, 0, 2, 0, 0, 0, 2, 0, -3, 8, -1, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 12, -6
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OFFSET
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1,12
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FORMULA
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A009223(n)-A066086(n)= GCD[Sigma(n)], Phi(n)]-GCD[Sigma[A007947(n)], Phi[A007947(n)]]
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EXAMPLE
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Frequently but not always zero. At n = 9, Phi[9] = 6, Sigma[9] = 13, GCD[6,13] = 1, kernel[9] = 3, Phi[3] = 2, Sigma[3] = 2, GCD[2,2,] = 2 and GCD[6,13]-GCD[2,2] = -1 = a(9); a(10) = GCD[4,18]-GCD[4,18] = 0, kernel(10) = 10; a(12) = GCD[4,28]-GCD[2,12] = 4-2 = 2, kernel(12) = 6.
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CROSSREFS
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A048250, A023900, A000203, A007947, A000010, A009223, A066086.
Sequence in context: A080225 A122841 A060862 this_sequence A080224 A010105 A083916
Adjacent sequences: A066084 A066085 A066086 this_sequence A066088 A066089 A066090
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KEYWORD
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sign
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Dec 04 2001
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