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 A076375 Both n and 2n are balanced numbers, are in A020492. 4
 1, 3, 6, 15, 35, 70, 105, 210, 357, 420, 1045, 1485, 2090, 2970, 3135, 3339, 5049, 5940, 6270, 10659, 12441, 12540, 16065, 24871, 24969, 29029, 33915, 35343, 39105, 39585, 49742, 50065, 58058, 58435, 64285, 70686, 71145, 74613, 78210, 87087 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Donovan Johnson, Table of n, a(n) for n = 1..1000 MATHEMATICA f[x_] := DivisorSigma[1, x]/EulerPhi[x] Do[s=f[n]; s1=f[2*n]; If[IntegerQ[s]&&IntegerQ[s1], Print[n]], {n, 1, 100000}] CROSSREFS Cf. A000010, A000203, A055234. Sequence in context: A173992 A027600 A024416 * A190586 A113225 A298539 Adjacent sequences:  A076372 A076373 A076374 * A076376 A076377 A076378 KEYWORD nonn AUTHOR Labos Elemer, Oct 15 2002 STATUS approved

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Last modified February 16 21:59 EST 2019. Contains 320200 sequences. (Running on oeis4.)