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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: A039629 A349296 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 September 11 21:59 EDT 2024. Contains 375839 sequences. (Running on oeis4.)