This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A352939 #41 Jul 13 2022 07:23:04 %S A352939 3,1,8,3,1,3,88,1,3,3,3,3,3,3,13,1,26,8,3,1,26,8,21,24,6,8,3,3,26,3, %T A352939 13,16,11,3,21,8,3,57,6,21,39,16,3,3,26,3,3,21,13,16,52,21,3,3,13,1, %U A352939 39,205,1,3,3,8,1,21,1,13,8,42,37,44,1,21,31,26,3,6,1,8,6,8,13,52,1,13,3,8,3,13,8,52,3,26,3 %N A352939 First differences of the records in the number of iterations of the 3x+1 sequences required to reach a power of 2. %C A352939 First differences of the records in the number of nonpowers of 2 in the sequences 3x+1. %C A352939 Is this a finite sequence? %C A352939 Closely related to A288493 (perhaps the same after initial terms). - _R. J. Mathar_, May 20 2022 %H A352939 Paolo Xausa, <a href="/A352939/b352939.txt">Table of n, a(n) for n = 1..146</a> (b-file generated using Eric Roosendaal's data and _Omar E. Pol_'s comment in A006877). %H A352939 Eric Roosendaal, <a href="http://www.ericr.nl/wondrous/delrecs.html">3x+1 Delay Records</a> %H A352939 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a> %e A352939 The first 10 terms of A208981 are 0, 0, 3, 0, 1, 4, 12, 0, 15, 2. The records are 0, 3, 4, 12, 15. The first differences of these records are 3, 1, 8, 3, the same as the first four terms of this sequence. %t A352939 f[n_] := -1 + Length @ NestWhileList[If[OddQ[#], 3*# + 1, #/2] &, n, ! IntegerQ @ Log[2, #] &]; Differences @ Union @ FoldList[Max, Array[f, 10^5]] (* _Amiram Eldar_, Apr 08 2022 *) %Y A352939 First differences of A352907. %Y A352939 Cf. A347270 (gives all 3x+1 sequences). %Y A352939 Cf. A006370, A006877, A014682, A056959, A057716, A208981, A347272, A347519, A347532, A353265. %K A352939 nonn %O A352939 1,1 %A A352939 _Omar E. Pol_, Apr 07 2022 %E A352939 More terms from _Paolo Xausa_, Jun 22 2022