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 A090044 #12 Apr 20 2015 04:23:19
%S A090044 2,2,2,2,1,2,2,0,0,2,2,2,0,2,2,2,1,2,2,1,2,2,0,0,1,0,0,2,2,2,0,1,1,0,
%T A090044 2,2,2,1,2,1,2,1,2,1,2,2,0,0,0,0,0,0,0,0,2,2,2,0,0,0,0,0,0,0,2,2,2,1,
%U A090044 2,0,0,0,0,0,0,2,1,2,2,0,0,2,0,0,0,0,0,2,0,0,2,2,2,0,2,2,0,0,0,0,2,2,0,2,2
%N A090044 Triangle read by rows: T(n,k) = A083093 with 1's and 2's interchanged.
%H A090044 Y. Moshe, <a href="http://dx.doi.org/10.1016/S0022-314X(03)00103-3">The density of 0's in recurrence double sequences</a>, J. Number Theory, 103 (2003), 109-121; see Fig. 1.
%H A090044 Y. Moshe, <a href="http://dx.doi.org/10.1016/j.disc.2005.03.022">The distribution of elements in automatic double sequences</a>, Discr. Math., 297 (2005), 91-103.
%F A090044 The negative of Pascal's triangle read mod 3.
%e A090044 2; 2,2; 2,1,2; 2,0,0,2; ...
%t A090044 -Mod[ Flatten[ Table[ Binomial[n, k], {n, 0, 13}, {k, 0, n}]], -3] (* _Robert G. Wilson v_, Jan 19 2004 *)
%Y A090044 Cf. A007318, A083093.
%K A090044 nonn,tabl,easy
%O A090044 0,1
%A A090044 _N. J. A. Sloane_, Jan 19 2004
%E A090044 Extended by _Robert G. Wilson v_, Jan 19 2004