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A078543
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Balanced refactorable numbers.
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1
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1, 2, 12, 56, 248, 12192, 28896, 60960, 61344, 66528, 86304, 94944, 129504, 133920, 140448, 182880, 201924, 207264, 242316, 282720, 408672, 416640, 426720, 429408, 604128, 664608, 671760, 776736, 792480, 854496, 862752, 906528
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| Donovan Johnson, Table of n, a(n) for n = 1..500
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FORMULA
| Intersection of A033950 and A020492.
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EXAMPLE
| n=56: tau(56)=8, sigma(56)=120, phi(56)=24, q1=120/24=5 for balancedness, q2=56/8=7 for refactorability
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MATHEMATICA
| Do[s=DivisorSigma[1, n]/EulerPhi[n]; If[ !IntegerQ[s]&&!PrimeQ[n], Print[n]], {n, 1, 256}]
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CROSSREFS
| Cf. A020492, A078538, A078539, A078540.
Sequence in context: A020522 A037130 A181298 * A084128 A044047 A105487
Adjacent sequences: A078540 A078541 A078542 * A078544 A078545 A078546
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Dec 04 2002
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