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Search: id:A082056
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| A082056 |
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Least x=a[n] such that sum of common prime-divisors [without multiplicity] of sigma[x] and phi[x] equals n; or 0 if such number (apparently) does not exist. |
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+0
2
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| 0, 3, 18, 0, 14, 0, 88, 1800, 116, 196, 9801, 377, 2881, 1189, 711, 989, 3596, 477, 6901, 5203, 8473, 9179, 3956, 7067, 6439, 27709, 41309, 10763, 27117, 20569, 10207, 69091, 4976, 15376, 114953, 18650, 204469, 37225, 16279, 130300, 74450, 10877
(list; graph; listen)
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OFFSET
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1,2
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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]}] t=Table[0, {100}]; Do[s=Apply[Plus, Intersection [ba[EulerPhi[n]], ba[DivisorSigma[1, n]]]]; If[s<101&&t[[s]]\[Equal]0, t[[s]]=n], {n, 2, 1000000}]; t
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CROSSREFS
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Cf. A000203, A000010, A082054, A082055.
Sequence in context: A051710 A162713 A161473 this_sequence A082057 A161687 A120647
Adjacent sequences: A082053 A082054 A082055 this_sequence A082057 A082058 A082059
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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 03 2003
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