OFFSET
1,1
MATHEMATICA
f[0] = 0; f[n_ /; 0 < n < 10^10] := 3*n - DivisorSigma[1, n]; f[_] = -1; Reap[For[k = 1, k < 3*10^4, k++, If[FixedPoint[f, k^2] == 0, Print[k^2]; Sow[k^2]]]][[2, 1]] (* Jean-François Alcover, Sep 17 2013 *)
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
EXTENSIONS
Better description from Jud McCranie, Dec 24 2000
More terms from Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 09 2006
STATUS
approved