reserve d,i,j,k,m,n,p,q,x,k1,k2 for Nat,
  a,c,i1,i2,i3,i5 for Integer;

theorem Th54:
  Fermat(4) = 256*256+1
proof
  thus Fermat(4) = 2 |^ (8 + 8) + 1 by POWER:62
    .= 2 |^ 8 * 2 |^ 8 + 1 by NEWTON:8
    .= (2 |^ 4 * 2 |^ 4)*2 |^ (4 + 4) + 1 by NEWTON:8
    .= 256*256+1 by NEWTON:8,POWER:62;
end;
