(* :Author: Christopher Moretti *) 
(* :Summary:Josephus[list,m,k] return a list of those places in -list- who will remain 
standing at the end of the Josephus problem
where every mth person is skipped starting with a. *) 
(* :History: Version 1.0 by Christopher Moretti, 1997 *) 

Clear[Josephus] 
Josephus[cycle_,m_,a_]:=Block[{newcyc,newcyc1,a1,len}, 
  len=Length[cycle];If[len<m,Return[cycle]]; 
  newcyc=cycle; 
  Do[ newcyc[[i m+a]]=0,{i,0,Floor[(len-a)/m]}]; 
  a1=Mod[Floor[(len-a)/m]m+a+m,len]; 
  If[a1==0,a1=m]; 
  newcyc1=Delete[Union[newcyc],1]; 
  Return[Josephus[newcyc1,m,a1]] 
 ];