%N Array T(m,n) = m*phi(n) - phi(mn) (m,n >= 1), read by antidiagonals.
%C It follows from the definition that m*phi(n) - phi(mn) >= 0.
%D D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 9.
%Y Cf. A000010, A076953, A079548, A079550.
%A _N. J. A. Sloane_, Jan 24 2003