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 A227840 #13 Sep 08 2022 08:46:05
%S A227840 0,0,0,0,1,0,0,0,2,1,0,1,0,0,0,0,0,4,0,0,0,1,1,0,1,0,0,0,0,0,1,0,0,0,
%T A227840 1,1,0,1,0,0,0,0,0,1,0,0,0,3,1,0,1,0,0,0,0,0,2,0,0,0,1,1,0,1,0,0,0,0,
%U A227840 0,1,0,0,0,1,1,0,1,0,0,0,0,0,1,0,0,0,2,1,0,1,0,0,0,0,0,2,0,0,0,1,1
%N A227840 3^a(n) is the highest power of 3 dividing A000110(n).
%C A227840 This is the 3-adic valuation of the Bell numbers A000110.
%C A227840 The 2-adic valuation is less interesting: 0, 0, 1, 0, 0, 2, 0, 0, 2, 0, 0, 1, 0, 0, 1, 0, 0, 2, 0, 0, 2, 0, 0, 1, 0, 0, 1, 0, 0, 2, 0, 0, 2, 0, 0, 1, 0, 0, 1, 0, 0, 2, 0, 0, 2, ...
%H A227840 Amiram Eldar, <a href="/A227840/b227840.txt">Table of n, a(n) for n = 0..10000</a>
%t A227840 Table[IntegerExponent[BellB[n], 3], {n, 0, 100}] (* _Amiram Eldar_, Nov 23 2019 *)
%o A227840 (Magma) [Valuation(Bell(n), 3): n in [0..110]]; // _Bruno Berselli_, Aug 05 2013
%Y A227840 Cf. A000110, A007949.
%K A227840 nonn
%O A227840 0,9
%A A227840 _N. J. A. Sloane_, Aug 05 2013