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A162692
Strictly positive numbers n such that 28*n/(28+n) are integers.
14
21, 28, 70, 84, 168, 364, 756
OFFSET
1,1
COMMENTS
The 28th row of A127730.
The ansatz 28*n/(28+n)=j (any integer j) yields n=28*j/(28-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=28; lst={}; Do[If[f[a, n]==IntegerPart[f[a, n]], AppendTo[lst, n]], {n, 9!}]; lst
CROSSREFS
Cf. A127730. [From Franklin T. Adams-Watters, Aug 07 2009]
Sequence in context: A254368 A276674 A130202 * A048067 A344603 A212192
KEYWORD
nonn,fini,full
AUTHOR
EXTENSIONS
Edited by R. J. Mathar, Jul 13 2009
STATUS
approved