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 A309954 #10 Aug 31 2019 07:00:19
%S A309954 0,1,2,3,0,1,2,3,0,2,4,6,0,3,6,9,0,0,0,0,0,1,2,3,0,2,4,6,0,3,6,9,0,0,
%T A309954 0,0,0,2,4,6,0,4,8,12,0,6,12,18,0,0,0,0,0,3,6,9,0,6,12,18,0,9,18,27,0,
%U A309954 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,2,3,0,2,4,6,0,3,6,9,0,0,0,0,0
%N A309954 Product of digits of (n written in base 4).
%H A309954 Seiichi Manyama, <a href="/A309954/b309954.txt">Table of n, a(n) for n = 0..10000</a>
%F A309954 G.f. A(x) satisfies: A(x) = x * (1 + 2*x + 3*x^2) * (1 + A(x^4)).
%t A309954 Table[Times @@ IntegerDigits[n, 4], {n, 0, 100}]
%Y A309954 Cf. A007090, A007954, A053737.
%K A309954 nonn,base
%O A309954 0,3
%A A309954 _Ilya Gutkovskiy_, Aug 24 2019