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 A230404 #13 Jan 05 2024 02:55:19
%S A230404 1,1,2,1,1,2,1,1,2,1,1,3,1,1,2,1,1,2,1,1,2,1,1,3,1,1,2,1,1,2,1,1,2,1,
%T A230404 1,3,1,1,2,1,1,2,1,1,2,1,1,3,1,1,2,1,1,2,1,1,2,1,1,4,1,1,2,1,1,2,1,1,
%U A230404 2,1,1,3,1,1,2,1,1,2,1,1,2,1,1,3,1,1
%N A230404 a(n) = the largest k such that (k+1)! divides 2n; the number of trailing zeros in the factorial base representation of even numbers.
%H A230404 Antti Karttunen, <a href="/A230404/b230404.txt">Table of n, a(n) for n = 1..10080</a>
%F A230404 a(n) = A230403(2n) = A055881(2n) - 1.
%F A230404 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = 2*e - 4 = A019762 - 4 = 1.436563... . - _Amiram Eldar_, Jan 05 2024
%o A230404 (Scheme)
%o A230404 (define (A230404 n) (A230403 (* 2 n)))
%Y A230404 Used to compute A230405 and A219650. See A007623 for factorial base representation.
%Y A230404 Analogous sequence for binary system: A001511.
%Y A230404 Cf. A019762.
%K A230404 nonn,easy
%O A230404 1,3
%A A230404 _Antti Karttunen_, Oct 31 2013