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%I #7 Nov 21 2013 12:49:39
%S 10,24,40,60,120,160,280,360,760,1560
%N Positive numbers n such that 40*n/(40+n) are integers.
%t f[a_,b_]:=(a*b)/(a+b); a=40;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]], AppendTo[lst,n]],{n,9!}];lst
%t Select[Range[1600],IntegerQ[(40#)/(40+#)]&] (* _Harvey P. Dale_, Oct 11 2011 *)
%Y Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694
%Y Cf. A127730. [From _Franklin T. Adams-Watters_, Aug 07 2009]
%K nonn,fini,full
%O 1,1
%A _Vladimir Joseph Stephan Orlovsky_, Jul 13 2009
%E Keywords fini,full added by _R. J. Mathar_, Jul 31 2009