OFFSET
1,1
MATHEMATICA
s[z_Complex] := DivisorSigma[1, z]-z; nn=10000; lst={}; Do[d=a^2+b^2; If[d<nn^2, z=a+b*I; Do[If[s[s[z]]==z, AppendTo[lst, {d, z}]]; z=z*I, {4}]], {a, nn}, {b, nn}]; Im[Transpose[Sort[lst]][[2]]]
CROSSREFS
KEYWORD
sign
AUTHOR
T. D. Noe, Jan 19 2005
STATUS
approved