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 A205562 Least positive integer j such that n divides (2k)!-(2j)!, where k, as in A205561, is the least number for which there is such a j. 0
 1, 1, 2, 2, 3, 2, 4, 2, 3, 3, 1, 2, 7, 4, 3, 3, 9, 3, 1, 3, 4, 1, 2, 2, 3, 7, 5, 4, 2, 3, 1, 4, 3, 9, 4, 3, 19, 1, 7, 3, 4, 4, 1, 3, 3, 2, 2, 3, 4, 3, 9, 7, 1, 5, 3, 4, 5, 2, 12, 3, 4, 1, 4, 4, 7, 3, 1, 9, 2, 4, 2, 3, 2, 19, 3, 5, 6, 7, 2, 3, 5, 4, 12, 4, 9, 1, 2, 3, 4, 3, 7, 2, 6, 2, 5, 4, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS For a guide to related sequences, see A204892. LINKS Table of n, a(n) for n=1..97. EXAMPLE 1 divides (2*2)!-(2*1)! -> k=2, j=1 2 divides (2*2)!-(2*1)! -> k=2, j=1 3 divides (2*3)!-(2*2)! -> k=3, j=2 4 divides (2*3)!-(2*2)! -> k=3, j=2 5 divides (2*4)!-(2*3)! -> k=4, j=3 MATHEMATICA s = Table[(2n)!, {n, 1, 120}]; lk = Table[NestWhile[# + 1 &, 1, Min[Table[Mod[s[[#]] - s[[j]], z], {j, 1, # - 1}]] =!= 0 &], {z, 1, Length[s]}] Table[NestWhile[# + 1 &, 1, Mod[s[[lk[[j]]]] - s[[#]], j] =!= 0 &], {j, 1, Length[lk]}] (* Peter J. C. Moses, Jan 27 2012 *) CROSSREFS Cf. A204892, A205551. Sequence in context: A141829 A111336 A083902 * A217984 A196437 A106491 Adjacent sequences: A205559 A205560 A205561 * A205563 A205564 A205565 KEYWORD nonn AUTHOR Clark Kimberling, Feb 01 2012 STATUS approved

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Last modified May 28 01:34 EDT 2024. Contains 372900 sequences. (Running on oeis4.)