cp's OEIS Frontend

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

%I A380138 #13 Jan 13 2025 11:37:59
%S A380138 1,2,16,16,52,52,52,88,9232,9232,9232,9232,9232,9232,9232,9232,9232,
%T A380138 9232,250504,190996,190996,250504,250504,250504,481624,975400,975400,
%U A380138 497176,11003416,11003416,106358020,18976192,41163712,106358020,21933016,104674192,593279152
%N A380138 a(n) is the largest value in the '3x+1' trajectory of starting points producing a record number of steps.
%H A380138 Hugo Pfoertner, <a href="/A380138/b380138.txt">Table of n, a(n) for n = 1..148</a>
%F A380138 a(n) = A025586(A006877(n)).
%t A380138 s = Map[ToExpression,
%t A380138   StringSplit[
%t A380138     Import["https://oeis.org/A006877/b006877.txt", "Data"][[2 ;; -1]]
%t A380138   ][[All, -1]] ];
%t A380138 Map[Max@ NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, #, # > 1 &] &, s] (* _Michael De Vlieger_, Jan 13 2025 *)
%Y A380138 Cf. A006877, A006878, A006884, A006885, A025586.
%K A380138 nonn
%O A380138 1,2
%A A380138 _Hugo Pfoertner_, Jan 13 2025