%I #6 Dec 04 2016 19:46:26
%S 1,1,3,2,1,3,1,2,3,1,2,3,4,1,5,4,1,3,3,5,3,2,1,4,5,4,6,3,4,5,2,4,4,1,
%T 7,3,6,3,4,5,5,3,8,2,6,1,4,4,7,5,3,4,2,6,6,7,3,4,2,5,8,2,7,4,13,4,5,3,
%U 4,7,7,6,4,6,5,3,11,4,9,5,9,5,3,3,5,8,4,4,8,6,13,4,11,4,13,4
%N Least positive integer j such that n divides 2k!-2j!, where k, as in A205563, is the least number for which there is such a j.
%C For a guide to related sequences, see A204892.
%e 1 divides 2*2!-2*1! -> k=2, j=1
%e 2 divides 2*2!-2*1! -> k=2, j=1
%e 3 divides 2*4!-2*3! -> k=4, j=3
%e 4 divides 2*3!-2*2! -> k=3, j=2
%e 5 divides 2*3!-2*1! -> k=3, j=1
%t s = Table[2n!, {n, 1, 120}];
%t lk = Table[
%t NestWhile[# + 1 &, 1,
%t Min[Table[Mod[s[[#]] - s[[j]], z], {j, 1, # - 1}]] =!= 0 &], {z, 1,
%t Length[s]}]
%t Table[NestWhile[# + 1 &, 1,
%t Mod[s[[lk[[j]]]] - s[[#]], j] =!= 0 &], {j, 1, Length[lk]}]
%t (* _Peter J. C. Moses_, Jan 27 2012 *)
%Y Cf. A204892.
%K nonn
%O 1,3
%A _Clark Kimberling_, Feb 01 2012