%I
%S 41,929,1301,30240,32760,260609,1441440,1860768,2178540,3205440,
%T 3378240,3423420,3914820,4029480,4437720,5738040,6093360,6807240,
%U 7136640,7239120,7551360,9402120,10204740,12270720,12405120,12942720,13495680,14627340,14725620
%N Let S(n)=sigma(n)/2n; sequence gives numbers n such that S(S(S(S(n))))=n. May be called {1,2}sociable number of orders 1 or 2 or 4.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/SociableNumbers.html">Sociable Numbers</a>
%Y Cf. A113285, A114528.
%K nonn
%O 1,1
%A _Yasutoshi Kohmoto_, Feb 15 2006
%E a(7)a(29) from _Charles R Greathouse IV_, Nov 12 2010.
