reserve a,b,i,k,m,n for Nat;
reserve s,z for non zero Nat;
reserve c for Complex;

theorem Th14:
  337 is prime
  proof
    for n being Element of NAT holds 1 < n & n*n <= 337 & n is prime implies
    not n divides 337
    proof
      let n be Element of NAT;
      337 = 2*168 + 1;
      then
A1:   not 2 divides 337;
      337 = 3*112 + 1;
      then
A2:   not 3 divides 337 by NAT_4:9;
      337 = 5*67 + 2;
      then
A3:   not 5 divides 337 by NAT_4:9;
      337 = 7*48 + 1;
      then
A4:   not 7 divides 337 by NAT_4:9;
      337 = 11*30 + 7;
      then
A5:   not 11 divides 337 by NAT_4:9;
      337 = 13*25 + 12;
      then
A6:   not 13 divides 337 by NAT_4:9;
      337 = 17*19 + 14;
      then
A7:   not 17 divides 337 by NAT_4:9;
      337 = 19*17 + 14;
      then
A8:   not 19 divides 337 by NAT_4:9;
      337 = 23*14 + 15;
      then
      not 23 divides 337 by NAT_4:9;
      hence thesis by A1,A2,A3,A4,A5,A6,A7,A8,NAT_4:62;
    end;
    hence thesis by NAT_4:14;
  end;
