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 A060412 In the '3x+1' problem, these values for the starting value set new records for the "dropping time", number of steps to reach a lower value than the start. 17
 2, 3, 7, 27, 703, 10087, 35655, 270271, 362343, 381727, 626331, 1027431, 1126015, 8088063, 13421671, 20638335, 26716671, 56924955, 63728127, 217740015, 1200991791, 1827397567, 2788008987, 12235060455 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The (3x+1)/2 steps and the halving steps are counted. - Don Reble, May 13 2006 Where records occur in A102419 (could be prefixed by an initial 1). - N. J. A. Sloane, Oct 20 2012 LINKS N. J. A. Sloane, Table of n, a(n) for n = 1..35 (from the web page of Tomás Oliveira e Silva) Tomás Oliveira e Silva, Tables Eric Roosendaal, On the 3x + 1 problem N. J. A. Sloane, First 36 terms of A217934 and A060412 [From Roosendaal web site] Index entries for sequences related to 3x+1 (or Collatz) problem EXAMPLE See A102419. MATHEMATICA dcoll[n_]:=Length[NestWhileList[If[EvenQ[#], #/2, 3#+1]&, n, #>=n&]]; t={max=2}; Do[If[(y=dcoll[n])>max, max=y; AppendTo[t, n]], {n, 3, 1130000, 4}]; t (* Jayanta Basu, May 28 2013 *) CROSSREFS A060413 gives associated "dropping times", A060414 the maximal values and A060415 the steps at which the maxima occur. See also A217934. Cf. A060445, A008884, A161021, A161022, A161023, A014682, A126241. Sequence in context: A052877 A137075 A270347 * A276665 A062573 A019435 Adjacent sequences: A060409 A060410 A060411 * A060413 A060414 A060415 KEYWORD nonn AUTHOR N. J. A. Sloane, Apr 06 2001; b-file added Nov 27 2007 STATUS approved

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Last modified April 20 06:23 EDT 2024. Contains 371799 sequences. (Running on oeis4.)