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A082070

Least common prime-divisor of Phi[n] and Sigma[1,n]=A000203(n); a(n)=1 if no common prime-divisor was found.

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1, 1, 2, 1, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 3, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 1, 2, 2, 2, 2, 2 (list; graph; listen)

	OFFSET	`1,3`
	MATHEMATICA	`ffi[x_] := Flatten[FactorInteger[x]] lf[x_] := Length[FactorInteger[x]] ba[x_] := Table[Part[ffi[x], 2*w-1], {w, 1, lf[x]}] f1[x_] := EulerPhi[x]; f2[x_] := DivisorSigma[1, x] Table[Min[Intersection[ba[f1[w]], ba[f2[w]]]], {w, 1, 128}]`
	CROSSREFS	`Cf. A000010, A000203, A082061-A082072.` `Adjacent sequences: A082067 A082068 A082069 this_sequence A082071 A082072 A082073` `Sequence in context: A026513 A106028 A105307 this_sequence A082071 A082902 A123926`
	KEYWORD	`nonn`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu), Apr 07 2003`

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Last modified October 10 20:39 EDT 2008. Contains 144831 sequences.

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