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Search: id:A080238
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| A080238 |
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Largest square-free number dividing sum of cubes of divisors of n. |
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+0
1
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| 1, 3, 14, 73, 42, 42, 86, 195, 757, 42, 222, 1022, 2198, 258, 42, 4681, 546, 2271, 70, 3066, 602, 222, 78, 2730, 15751, 6594, 5110, 6278, 8130, 42, 266, 4161, 1554, 546, 1806, 55261, 50654, 210, 2198, 2730, 22974, 1806, 39754, 16206, 31794, 78, 4326
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OFFSET
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1,2
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FORMULA
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a(n)=A007947[A001158(n)]
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EXAMPLE
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n=12: sigma3[12]=1+8+27+64+216+1728=2044, sqf-kernel=1022=a(12)
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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]}] cor[x_] := Apply[Times, ba[x]] Table[cor[DivisorSigma[3, w]], {w, 1, 100}]
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CROSSREFS
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Cf. A000213, A007947, A001157.
Sequence in context: A098648 A026295 A118650 this_sequence A074549 A126122 A026004
Adjacent sequences: A080235 A080236 A080237 this_sequence A080239 A080240 A080241
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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), Mar 19 2003
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