OFFSET
1,1
COMMENTS
The 20th row of A127730.
The ansatz 20*n/(20+n)=j (any integer j) yields n=20*j/(20-j) which demonstrates that the sequence is finite if n>=0. [R. J. Mathar, Jul 13 2009]
MATHEMATICA
f[a_, b_]:=(a*b)/(a+b); a=20; lst={}; Do[If[f[a, n]==IntegerPart[f[a, n]], AppendTo[lst, n]], {n, 9!}]; lst
CROSSREFS
KEYWORD
nonn,fini,full
AUTHOR
Vladimir Joseph Stephan Orlovsky, Jul 10 2009
EXTENSIONS
Edited by R. J. Mathar, Jul 13 2009
STATUS
approved