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 A078543 Balanced refactorable numbers. 2
 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; text; internal format)
 OFFSET 1,2 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 (calculated using data from Jud McCranie, terms 1..500 from Donovan Johnson) EXAMPLE n=56: tau(56)=8, sigma(56)=120, phi(56)=24, q1=120/24=5 for balancedness, q2=56/8=7 for refactorability. MATHEMATICA Do[s=DivisorSigma[1, n]/EulerPhi[n]; If[ !IntegerQ[s]&&!PrimeQ[n], Print[n]], {n, 1, 256}] CROSSREFS Intersection of A033950 and A020492. Cf. A078538, A078539, A078540. Sequence in context: A037130 A181298 A247121 * A084128 A044047 A296944 Adjacent sequences:  A078540 A078541 A078542 * A078544 A078545 A078546 KEYWORD nonn AUTHOR Labos Elemer, Dec 04 2002 STATUS approved

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Last modified August 1 17:43 EDT 2021. Contains 346402 sequences. (Running on oeis4.)