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A096988 Initial values for f(x)=sigma(phi(x))=A062402(x) such that iteration of f ends in cycle of length=1. 1
1, 2, 3, 4, 6, 13, 15, 16, 20, 21, 23, 24, 25, 26, 28, 30, 33, 36, 42, 44, 46, 50, 66, 157, 169, 203, 215, 237, 241, 245, 255, 256, 261, 272, 275, 287, 303, 305, 314, 316, 320, 325, 338, 340, 344, 347, 367, 369, 375, 384, 385, 392, 393, 404, 406, 408, 429, 430 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..10000

MATHEMATICA

a = {}; Do[s = {n}; While[! MemberQ[s, k = DivisorSigma[1, EulerPhi[s[[-1]]]]], AppendTo[s, k]]; If[s[[-1]] == k, AppendTo[a, n]], {n, 430}]; a (* Ivan Neretin, Dec 15 2016 *)

CROSSREFS

Cf. A062402, A095952, A018784.

Sequence in context: A018738 A018765 A274694 * A066463 A073146 A038767

Adjacent sequences:  A096985 A096986 A096987 * A096989 A096990 A096991

KEYWORD

nonn

AUTHOR

Labos Elemer, Jul 19 2004

STATUS

approved

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Last modified July 30 17:21 EDT 2021. Contains 346359 sequences. (Running on oeis4.)