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 A306546 #25 Apr 27 2019 07:36:12 %S A306546 4,1,10,1,16,3,22,1,28,5,34,3,40,7,46,1,52,9,58,5,64,11,70,3,76,13,82, %T A306546 7,88,15,94,1,100,17,106,9,112,19,118,5,124,21,130,11,136,23,142,3, %U A306546 148,25,154,13,160,27,166,7,172,29,178,15,184,31,190,1,196,33,202,17,208,35,214,9,220,37,226,19,232 %N A306546 Modified Collatz Map such that odd numbers are treated the same, but even numbers have all factors of 2 removed. %C A306546 All numbers that reach 1 under normal Collatz iteration will reach 1 through this mapping. This sequence combines all consecutive even number halvings into one step. This will decrease steps to completion compared to normal Collatz iteration for all starting points other than 1 and 2, drastically in most cases. If this mapping is applied upon A000265, the sequence generated when the even operation is applied initially, then further iteration through this modified mapping will have all entries synchronize to all either be odd or all be even for any given step. %H A306546 Aidan Simmons, <a href="/A306546/b306546.txt">Table of n, a(n) for n = 1..10000</a> %H A306546 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a> %F A306546 For any even n, a(n) = A000265(n). For any odd n, a(n) = 3n+1. %o A306546 (PARI) a(n) = if (n%2, 3*n+1, n >> valuation(n, 2)); \\ _Michel Marcus_, Mar 05 2019 %Y A306546 Cf. A006370, A016777, A000265. %K A306546 nonn,easy %O A306546 1,1 %A A306546 _Aidan Simmons_, Feb 22 2019