%N Even refactorable numbers n such that the number r of odd divisors is odd, the number s of even divisors is even, both r and s are divisors of n and n is the first number for which the triple (r,s,t) occurs, where t is the number of divisors of n.
%C Note that s is necessarily a multiple of r.
%e a(1)=36 since r=3, s=6 and r+s=9.
%Y Cf. A033950, A049439. A057265.
%A _Walter Kehowski_, Jun 25 2006