reserve X for set;
reserve a,b,c,k,m,n for Nat;
reserve i for Integer;
reserve r for Real;
reserve p for Prime;

theorem
  561 divides 2|^561-2
  proof
A1: 561 = 3*11*17;
    3,11,17 are_mutually_coprime by PEPIN:41,60,NAT_4:27,INT_2:30;
    hence thesis by A1,Th37,Th38,Th39,Th12;
  end;
