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A076377
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n, 2n, 4n, 8n are balanced numbers, all are in A020492.
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1
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105, 1485, 3135, 35343, 39105, 71145, 74613, 87087, 124605, 150195, 175305, 192855, 263055, 413655, 421005, 697851, 930699, 1404765, 1873485, 2471931, 2576115, 2965599, 3281265, 3398625, 4172259, 4532625, 4589949, 4975965
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Sigma[u]/Phi[u]=q=quotients for u={n,2n,4n,8n} are integer and for all terms equal 4,12,14,15 respectively. For 16n q=31/2, i.e. not yet[u<6000000] integer were found.
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MATHEMATICA
| f[x_] := DivisorSigma[1, x]/EulerPhi[x] Do[s=f[n]; s1=f[2*n]; s2=f[4*n]; s3=f[8*n] If[IntegerQ[s]&&IntegerQ[s1]&&IntegerQ[s2]&& IntegerQ[s3], Print[n]], {n, 1, 10000000}]
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CROSSREFS
| Cf. A000010, A000203, A055234, A020492, A076375, A076376.
Sequence in context: A058844 A165382 A051015 * A165374 A024198 A027788
Adjacent sequences: A076374 A076375 A076376 * A076378 A076379 A076380
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Oct 15 2002
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