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

Author

Hugo Pfoertner, Jan 13 2025

Keywords

• nonn

Links

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

Crossrefs

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

Programs

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 *)

Formula

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