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A074886 Numbers n such that sigma(sigma(n) - n) = phi(sigma(n) + n). 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..1000

EXAMPLE

sigma(sigma(110)-110) = sigma(216-110) = 162; phi(sigma(110)+110) = phi(326) = 162, so 110 is a term of the sequence.

MATHEMATICA

r = {}; Do[d = DivisorSigma[1, n]; If[DivisorSigma[1, d - n] == EulerPhi[d + n], r = Append[r, n]], {n, 1, 10^5}]; r

CROSSREFS

Cf. A000010, A000203, A001065, A155085.

Sequence in context: A020327 A039629 A205493 * A294445 A036395 A271561

Adjacent sequences:  A074883 A074884 A074885 * A074887 A074888 A074889

KEYWORD

nonn

AUTHOR

Joseph L. Pe, Sep 13 2002

STATUS

approved

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Last modified May 31 06:45 EDT 2020. Contains 334747 sequences. (Running on oeis4.)