%I #2 Mar 30 2012 17:40:36
%S 1,3,42,77,1517,4238484
%N n*phi(n)*phi(phi(n)) is a triangular number.
%e 1517*phi(1517)*phi(phi(1517))=T(40959).
%Y Cf. A116002.
%K nonn
%O 1,2
%A _Giovanni Resta_, Feb 13 2006
