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Search: id:A070008
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| A070008 |
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Arithmetical mean of distinct primes dividing n is a power of 2 (n=powers of 2 are not left out). |
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+0
1
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| 2, 4, 8, 15, 16, 32, 39, 42, 45, 55, 64, 75, 84, 87, 114, 117, 126, 128, 135, 168, 170, 183, 225, 228, 247, 252, 256, 258, 261, 275, 294, 295, 336, 340, 342, 351, 375, 378, 405, 410, 456, 504, 507, 512, 516, 549, 583, 588, 605, 672, 675, 680, 684, 756, 774
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OFFSET
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1,1
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EXAMPLE
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n=9189=3.1021, mean=(3+1021)/2=512.
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MATHEMATICA
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ffi[x_] := Flatten[FactorInteger[x]] lf[x_] := Length[FactorInteger[x]] ba[x_] := Table[Part[ffi[x], 2*w-1], {w, 1, lf[x]}] Do[s=Apply[Plus, ba[n]]/lf[n]; If[IntegerQ[Log[2, s]], Print[{n, s}]], {n, 2, 10000}]
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CROSSREFS
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Cf. A070005-A070007, A008472, A001414.
Sequence in context: A076351 A140117 A039743 this_sequence A033623 A094398 A026474
Adjacent sequences: A070005 A070006 A070007 this_sequence A070009 A070010 A070011
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Apr 11 2002
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