A352907 - OEIS

%I #49 Jul 26 2022 14:03:21

%S 0,3,4,12,15,16,19,107,108,111,114,117,120,123,126,139,140,166,174,

%T 177,178,204,212,233,257,263,271,274,277,303,306,319,335,346,349,370,

%U 378,381,438,444,465,504,520,523,526,552,555,558,579,592,608,660,681,684

%N Records in the number of iterations in the 3x+1 sequences required to reach a power of 2.

%C Records of the number of nonpowers of 2 in the sequences 3x+1.

%C Is this a finite sequence?

%H Paolo Xausa, <a href="/A352907/b352907.txt">Table of n, a(n) for n = 1..147</a> (b-file generated using Eric Roosendaal's data and _Omar E. Pol_'s comment in A006877).

%H Eric Roosendaal, <a href="http://www.ericr.nl/wondrous/delrecs.html">3x+1 Delay Records</a>

%H <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a>

%t f[n_] := -1 + Length @ NestWhileList[If[OddQ[#], 3*# + 1, #/2] &, n, !IntegerQ @ Log[2, #] &]; Union @ FoldList[Max, Array[f, 10^5]] (* _Amiram Eldar_, Apr 08 2022 *)

%Y Records in A208981.

%Y Cf. A352939 (first differences).

%Y Cf. A347270 (gives all 3x+1 sequences).

%Y Cf. A006370, A006877, A014682, A056959, A057716, A347272, A347519, A347532, A353265.

%K nonn

%O 1,2

%A _Omar E. Pol_, Apr 07 2022

%E More terms from _Alois P. Heinz_, Apr 07 2022