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A074886
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Numbers n such that sigma(sigma(n) - n) = phi(sigma(n) + n).
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1
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14, 110, 274, 435, 1298, 4608, 4646, 5384, 9214, 10154, 10778, 11912, 13035, 13844, 15026, 18698, 21346, 22958, 25642, 26846, 27466, 32078, 34546, 41164, 49570, 77374, 80438, 85875
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OFFSET
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1,1
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LINKS
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Amiram Eldar, Table of n, a(n) for n = 1..1000
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EXAMPLE
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sigma(sigma(110)-110) = sigma(216-110) = 162; phi(sigma(110)+110) = phi(326) = 162, so 110 is a term of the sequence.
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MATHEMATICA
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r = {}; Do[d = DivisorSigma[1, n]; If[DivisorSigma[1, d - n] == EulerPhi[d + n], r = Append[r, n]], {n, 1, 10^5}]; r
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CROSSREFS
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Cf. A000010, A000203, A001065, A155085.
Sequence in context: A020327 A039629 A205493 * A294445 A036395 A271561
Adjacent sequences: A074883 A074884 A074885 * A074887 A074888 A074889
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KEYWORD
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nonn
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AUTHOR
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Joseph L. Pe, Sep 13 2002
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STATUS
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approved
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