OFFSET
1,2
FORMULA
a(n) = Min{x; A082055(x)=n}; 0 if n is not squarefree.
EXAMPLE
For n = 85: a(85) = 924800 = 128*5*5*17*17; sigma(924800) = 2426835 = 3*5*17*31*307; phi(924800) = 348160 = 4096*5*17; common prime factor 5.17 = 85.
MATHEMATICA
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[Times, Intersection
[ba[EulerPhi[n]], ba[DivisorSigma[1, n]]]];
If[s<101&&t[[s]]==0, t[[s]]=n], {n, 1, 1000000}]; t
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Apr 03 2003
EXTENSIONS
Corrected and extended by David Wasserman, Aug 27 2004
STATUS
approved