A162828 Positive numbers n such that 2*90*n/(90+n) are integers.

10, 18, 30, 45, 60, 72, 90, 110, 126, 135, 180, 210, 234, 270, 315, 360, 450, 510, 558, 585, 720, 810, 990, 1260, 1530, 1710, 1935, 2610, 3150, 3960, 5310, 8010, 16110

Offset

1,1

Links

Table of n, a(n) for n=1..33.

Mathematica

f[a_, b_]:=(a*b)/(a+b)*2; a=90; lst={}; Do[If[f[a, n]==IntegerPart[f[a, n]], AppendTo[lst, n]], {n, 9!}]; lst
Select[Range[17000], IntegerQ[180 #/(#+90)]&] (* Harvey P. Dale, Sep 22 2011 *)

Crossrefs

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

Sequence in context: A100992 A256382 A167607 * A190038 A233695 A014006

Adjacent sequences: A162825 A162826 A162827 * A162829 A162830 A162831

Keyword

nonn,fini,full

Author

Vladimir Joseph Stephan Orlovsky, Jul 13 2009

Extensions

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

Status

approved