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 A372447 #5 May 03 2024 15:41:18
%S A372447 4,5,4,5,6,6,7,6,6,7,6,7,7,7,8,8,9,8,7,7,8,8,8,8,8,9,10,10,11,9,10,11,
%T A372447 11,9,8,8,5,4,5,5,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
%U A372447 0,0,0,0,0,0,0
%N A372447 a(n) = A000523(A372443(n)); One less than the binary length of the n-th iterate of 27 with Reduced Collatz-function R.
%H A372447 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a>
%o A372447 (PARI)
%o A372447 A000265(n) = (n>>valuation(n,2));
%o A372447 A000523(n) = logint(n,2);
%o A372447 A372443(n) = { my(x=27); while(n, x=A000265(3*x+1); n--); (x); };
%o A372447 A372447(n) = A000523(A372443(n));
%Y A372447 Cf. A000523, A372443.
%K A372447 nonn
%O A372447 0,1
%A A372447 _Antti Karttunen_, May 03 2024