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%I #14 Mar 27 2017 03:10:16
%S 3,2,3,3,3,2,3,4,6,6,9,9,9,8,6,5,6,4,6,7,6,5,6,6,6,8,8,9,12,12,12,14,
%T 13,12,15,18,18,12,18,20,21,20,21,21,21,20,21,20,21,24,24,20,27,26,27,
%U 20,20,16,18,21,21,21,19,18,27,30,33,33,33,48,51,42
%N a(n) = A211384(2n)/A211384(n).
%H Alois P. Heinz, <a href="/A242309/b242309.txt">Table of n, a(n) for n = 1..10000</a>
%e a(11) = 9 because A211384(22) = 198 and A211384(11) = 22 and 198/22 = 9.
%p b:= proc(n) b(n):= `if`(n<3, 2*n-1, (h-> ceil((b(n-1)+1)/h)*h)
%p (ilcm(map(b, numtheory[divisors](n) minus {1, n})[]))) end:
%p a:= n-> b(2*n)/b(n):
%p seq(a(n), n=1..100); # _Alois P. Heinz_, May 20 2014
%t b[1] = 1; b[2] = 3; b[n_] := b[n] = (Ceiling[(b[n-1]+1)/#]*#&)[LCM @@ Map[b, Most[Divisors[n]]]];
%t a[n_] := b[2n]/b[n];
%t Table[a[n], {n, 1, 80}] (* _Jean-François Alcover_, Mar 27 2017, after _Alois P. Heinz_ *)
%Y Cf. A211384.
%K nonn,look
%O 1,1
%A _J. Lowell_, May 10 2014
%E More terms from _Alois P. Heinz_, May 10 2014
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