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 A169590 #3 Sep 08 2013 13:31:50
%S A169590 1,2,1,1,0,1,2,0,2,1,1,0,1,0,1,2,0,2,0,2,1,1,0,1,0,1,0,1,2,0,2,0,2,0,
%T A169590 2,1,1,0,1,0,1,0,1,0,1,2,0,2,0,2,0,2,0,2,1,1,0,1,0,1,0,1,0,1,0,1,2,0,
%U A169590 2,0,2,0,2,0,2,0,2,1,1,0,1,0,1,0,1,0,1,0,1,0,1,2,0,2,0,2,0,2,0,2,0,2,0,2,1
%N A169590 Triangle T(n,k) with : column n = A000034 if n even and column n = A000007 if n odd.
%C A169590 Row sums : A145051.
%F A169590 Sum_{k, 0<=k<=n} T(n,k)= A145051(n+1).
%e A169590 Triangle begins: 1 ; 2,1 ; 1,0,1 ; 2,0,2,1 ; 1,0,1,0,1 ; 2,0,2,0,2,1 ; ...
%K A169590 nonn,tabl
%O A169590 0,2
%A A169590 _Philippe Deléham_, Dec 02 2009