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A078541
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Refactorable numbers x, such that quotient x/A000005(x) equals a power of 2.
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0
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1, 2, 8, 12, 36, 80, 96, 128, 288, 448, 2560, 6144, 11264, 18432, 32768, 53248, 57344, 245760, 737280, 1114112, 2621440, 4980736, 22020096, 23068672, 25165824, 66060288, 75497472, 96468992, 436207616, 939524096, 1258291200, 1811939328, 2147483648, 3774873600
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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FORMULA
| a(n)/tau(a(n))=2^s with some s, tau()=A000005()
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EXAMPLE
| a(6)=80: tau(80)=10, quotient=80/10=8=2^3; certain powers of 2 do not appear as quotient, like 64, 1024, 16384.
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MATHEMATICA
| Do[s=n/DivisorSigma[0, n]; If[IntegerQ[Log[2, s]], Print[{n, s, n/s}]], {n, 1, 1000000000}]
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CROSSREFS
| Cf. A000005, A033950, A036763, A051278, A051279, A051280.
Sequence in context: A125712 A062290 A176961 * A135443 A143231 A104039
Adjacent sequences: A078538 A078539 A078540 * A078542 A078543 A078544
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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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EXTENSIONS
| a(29)-a(34) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Jun 04 2011
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