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A162829
Positive numbers n such that 2*120*n/(120+n) are integers.
0
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
1,1
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 *)
KEYWORD
nonn,fini,full
AUTHOR
EXTENSIONS
Sign in definition flipped by R. J. Mathar, Jul 31 2009
STATUS
approved