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%I #9 Mar 14 2020 19:06:48
%S 6,14,21,24,28,30,33,35,36,38,39,40,41,42,43,44,45,46,48,49,51,54,56,
%T 60,63,70,78,84,91,105,126,140,168,189,238,294,336,483,630,924,1806
%N Positive numbers k such that 42*k/(42-k) are integers.
%C The number k=42 is explicitly included, treating the result of division through zero as an integer.
%C Row 42 of A191973.
%p for m from 1 to 1806 do if(m=42 or m*42 mod (m-42) = 0)then printf("%d, ", m): fi: od: # _Nathaniel Johnston_, Jun 22 2011
%t f[a_,b_]:=(a*b)/(a-b); a=42;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]], AppendTo[lst,n]],{n,9!}];lst
%t Join[{42},Select[Range[2000],IntegerQ[(42#)/(42-#)]&]]//Quiet//Sort (* _Harvey P. Dale_, Mar 14 2020 *)
%Y Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694, A162817, A162818, A162819, A162820, A162821, A162822, A191973.
%K nonn,fini,full,easy
%O 1,1
%A _Vladimir Joseph Stephan Orlovsky_, Jul 13 2009
%E Keywords fini,full added by _R. J. Mathar_, Jul 31 2009