%I #15 Jul 08 2016 03:33:02
%S 1441440,1860768,3205440,3378240,3423420,3914820,4029480,4437720,
%T 5738040,6093360,6807240,7136640,7239120,7551360,9402120,10204740,
%U 12270720,12405120,12942720,13495680,14627340,14725620,15233400,17166240,18097800,19158048,23023440
%N Numbers n such that there exists an x!=n that makes {n,n,x,x} an amicable multiset.
%C We call the multiset {n,n,x,x} amicable iff sigma(n)=sigma(x)=n+n+x+x.
%C If the condition x!=n were dropped, the terms from A027687 would also belong here.
%H John Cerkan, <a href="/A259306/b259306.txt">Table of n, a(n) for n = 1..1000</a>
%o (PARI) isOK(n) = x=(sigma(n)-2*n)/2; x>0 && x!=n && denominator(x)==1 && sigma(x)==n+n+x+x
%Y Cf. A027687, A259307, A259302, A259303, A259304, A259305, A036471.
%K nonn
%O 1,1
%A _Jeppe Stig Nielsen_, Jun 23 2015