A162688 Strictly positive numbers n such that 12*n/(12+n) are integers.

4, 6, 12, 24, 36, 60, 132

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Jul 10 2009

Keywords

• nonn
• fini
• full

Comments

The 12 row of A127730.

The ansatz 12*n/(12+n)=j (any integer j) yields n=12*j/(12-j) which demonstrates that the sequence is finite if n>=0. [R. J. Mathar, Jul 13 2009]

Crossrefs

Cf. A127730. [From Franklin T. Adams-Watters, Aug 07 2009]

Programs

Mathematica

f[a_,b_]:=(a*b)/(a+b); a=12;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]],AppendTo[lst,n]],{n,9!}];lst

Extensions

Edited by R. J. Mathar, Jul 13 2009