A162821 Positive numbers k such that 30*k/(30-k) are integers.

5, 10, 12, 15, 18, 20, 21, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 39, 40, 42, 45, 48, 50, 55, 60, 66, 75, 80, 90, 105, 120, 130, 180, 210, 255, 330, 480, 930

Offset

1,1

Comments

The number k=30 is explicitly included, treating the result of division through zero as an integer.

Row 30 of A191973.

Links

Table of n, a(n) for n=1..41.

Maple

for m from 1 to 930 do if(m=30 or m*30 mod (m-30) = 0)then printf("%d, ", m): fi: od: # Nathaniel Johnston, Jun 22 2011

Mathematica

f[a_, b_]:=(a*b)/(a-b); a=30; lst={}; Do[If[f[a, n]==IntegerPart[f[a, n]], AppendTo[lst, n]], {n, 9!}]; lst

Crossrefs

Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694, A162817, A162818, A162819, A162820, A191973.

Sequence in context: A050680 A293726 A313359 * A313360 A313361 A059324

Adjacent sequences: A162818 A162819 A162820 * A162822 A162823 A162824

Keyword

nonn,fini,full,easy

Author

Vladimir Joseph Stephan Orlovsky, Jul 13 2009

Extensions

Keywords fini,full added by R. J. Mathar, Jul 31 2009

Status

approved