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%I #9 Jan 27 2014 12:16:57
%S 1,0,0,6,12,20,12,42,24,18,15,110,24,156,35,30,48,272,36,342,30,28,99,
%T 506,40,100,143,54,70,812,45,930,96,66,255,140,45,1332,323,78,60,1640,
%U 56,1806,77,90,483,2162,80,294,75,102,117,2756,108,66,140,114,783
%N Least integer k > n such that n*k/(n+k) is an integer, or 0 if no such k exists.
%D a(3) = 6 because 6 is the smallest k > 3 such that k*3/(k+3) is an integer.
%H Giovanni Resta, <a href="/A235268/b235268.txt">Table of n, a(n) for n = 0..1000</a>
%F For prime p, a(p) = p*(p-1) = A002378(p-1). - _Ralf Stephan_, Jan 15 2014
%t a[0]=1; a[n_] := Block[{k,s,x}, s = Reduce[k*n/(k+n) == x && k>n, {k,x}, Integers]; If[s === False, 0, Min[k /. List@ ToRules@s]]]; a/@Range[0,100] (* _Giovanni Resta_, Jan 20 2014 *)
%o (PARI) a(n)=my(k=n+1);while((n*k)%(n+k)!=0,k=k+1);k \\ _Ralf Stephan_, Jan 15 2014
%Y Cf. A063427.
%K nonn
%O 0,4
%A _Alex Ratushnyak_, Jan 05 2014
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