A162829 Positive numbers n such that 2*120*n/(120+n) are integers.

8, 24, 30, 40, 60, 72, 80, 105, 120, 168, 180, 200, 240, 264, 280, 330, 360, 456, 480, 520, 600, 680, 780, 840, 1032, 1080, 1320, 1480, 1680, 1800, 2280, 2760, 3080, 3480, 4680, 5640, 7080, 9480, 14280, 28680

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Jul 13 2009

Keywords

• nonn
• fini
• full

Crossrefs

Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694, A162817, A162818, A162819, A162820, A162821, A162822, A162823, A162824, A162825, A162826, A162828

Programs

Mathematica

f[a_,b_]:=(a*b)/(a+b)*2; a=120;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]], AppendTo[lst,n]],{n,9!}];lst
Select[Range[30000],IntegerQ[240 #/(120+#)]&] (* Harvey P. Dale, Apr 09 2014 *)

Extensions

Sign in definition flipped by R. J. Mathar, Jul 31 2009