A380138 a(n) is the largest value in the '3x+1' trajectory of starting points producing a record number of steps.

1, 2, 16, 16, 52, 52, 52, 88, 9232, 9232, 9232, 9232, 9232, 9232, 9232, 9232, 9232, 9232, 250504, 190996, 190996, 250504, 250504, 250504, 481624, 975400, 975400, 497176, 11003416, 11003416, 106358020, 18976192, 41163712, 106358020, 21933016, 104674192, 593279152

Offset

1,2

Links

Hugo Pfoertner, Table of n, a(n) for n = 1..148

Formula

a(n) = A025586(A006877(n)).

Mathematica

s = Map[ToExpression,
  StringSplit[
    Import["https://oeis.org/A006877/b006877.txt", "Data"][[2 ;; -1]]
  ][[All, -1]] ];
Map[Max@ NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, #, # > 1 &] &, s] (* Michael De Vlieger, Jan 13 2025 *)

Crossrefs

Cf. A006877, A006878, A006884, A006885, A025586.

Sequence in context: A263355 A066773 A138761 * A087970 A247634 A261617

Adjacent sequences: A380135 A380136 A380137 * A380139 A380140 A380141

Keyword

nonn

Author

Hugo Pfoertner, Jan 13 2025

Status

approved