is a sequence of finite initial segments (1, ..., n) of natural numbers. It contains every natural number that can be somewhere. Every number in the sequence T is in one line L_n and in all further lines by construction of T (always the last line is added). Every number in T is in the first column C (and in every other column too).
forall n : (1, ..., n) c C ==> (1, ..., n) e T forall n : (1, ..., n) e T ==> (1, ..., n) c C
Therefore it is impossible that C contains more than T and more than any line L_n of T. But we know that there is no line L_n with an actually infite set |N of numbers (because T is a sequence of finite lines L_n). Conclusion: An actually infinite set |N cannot be in the first column either (and nowhere else).