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 A251542 List of values A098550(n+2)/A098550(n) for those n for which A098550(n) is a prime. 8
 2, 3, 5, 3, 3, 2, 5, 5, 5, 2, 3, 3, 2, 3, 7, 5, 3, 7, 5, 3, 5, 3, 7, 3, 7, 5, 3, 3, 5, 5, 3, 5, 3, 7, 7, 5, 5, 7, 5, 3, 5, 7, 7, 3, 5, 3, 3, 5, 5, 3, 3, 7, 3, 3, 5, 3, 5, 7, 3, 5, 7, 3, 3, 5, 11, 3, 5, 5, 5, 3, 5, 5, 5, 5, 7, 3, 7, 5, 5, 7, 3, 5, 5, 3, 3, 5, 3, 7, 7, 5 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) <= 17 for n <= 250000 (see A251543). For n > 4: third column in A251715. - Reinhard Zumkeller, Dec 16 2014 a(n) <= 19 for n <= 10^6. - Chai Wah Wu, Dec 16 2014 LINKS Chai Wah Wu, Table of n, a(n) for n = 1..10000 David L. Applegate, Hans Havermann, Bob Selcoe, Vladimir Shevelev, N. J. A. Sloane, and Reinhard Zumkeller, The Yellowstone Permutation, arXiv preprint arXiv:1501.01669, 2015 and J. Int. Seq. 18 (2015) 15.6.7. EXAMPLE A098550(n) for n= 1..11 is 1,2,3,4,9,8,15,14,5,6,25. Each time you see a prime, divide the term two steps ahead by that prime. The result is 4/2=2, 9/3=3, 25/5=5,... MATHEMATICA max = 1200; f[lst_] := Block[{k = 4}, While[GCD[lst[[-2]], k] == 1 || GCD[lst[[-1]], k] > 1 || MemberQ[lst, k], k++]; Append[lst, k]]; A098550 = Nest[f, {1, 2, 3}, max - 3]; sel = Select[Transpose[{Range[max], A098550}], PrimeQ[#[[2]]]&][[All, 1]]+2; A098550[[sel]]/A098550[[sel - 2]] (* Jean-François Alcover, Sep 05 2018, after Robert G. Wilson v in A098550 *) PROG (Haskell) a251542 n = a251542_list !! (n-1) a251542_list = [div u v | (u, v) <- zip(drop 2 a098550_list) a098550_list,                           a010051' v == 1] -- Reinhard Zumkeller, Mar 11 2015 CROSSREFS Cf. A098550, A251543. See A251544 for the actual values of A098550(n+2). Cf. A251715. Sequence in context: A337583 A172984 A072751 * A131971 A321882 A281158 Adjacent sequences:  A251539 A251540 A251541 * A251543 A251544 A251545 KEYWORD nonn AUTHOR David Applegate and N. J. A. Sloane, Dec 15 2014 STATUS approved

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Last modified June 15 00:00 EDT 2021. Contains 345041 sequences. (Running on oeis4.)