%I #14 Nov 21 2013 13:11:41

%S 1,3,18,36

%N Numbers n such that n=tau_3(n)=A007425(n).

%C Also, numbers n such that n = sum_d|n (tau(d)), (i.e. n is equal to the total number of divisors of all divisors of n ). - _Lekraj Beedassy_, Jul 12 2008

%D J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 36, pp 14, Ellipses, Paris 2008.

%D J.-M. De Koninck & A. Mercier, 1001 Problemes en Theorie Classique Des Nombres, Problem 712 pp. 93;305 Ellipses Paris 2004.

%t Select[Range[10^5],Total[(DivisorSigma[0,#]&) /@ Divisors[#]] == #&](* _Jean-François Alcover_, Sep 14 2011 *)

%K fini,full,nonn

%O 1,2

%A _Lekraj Beedassy_, Sep 07 2004