reserve a,b,k,m,n,s for Nat;
reserve c,c1,c2,c3 for Complex;
reserve i,j,z for Integer;
reserve p for Prime;
reserve x for object;

theorem Th29:
  card divisors(3|^(2*n+1),4,1) = n+1
  proof
    divisors(3|^(2*n+1),4,1) = { 3|^m: m is even & m <= 2*n+1 } by Th25;
    hence thesis by Th27;
  end;
