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 A113998 #5 Sep 08 2013 13:30:50
%S A113998 1,1,1,1,0,1,1,0,1,1,1,0,0,0,1,1,0,0,1,1,1,1,0,0,0,0,0,1,1,0,0,0,1,0,
%T A113998 1,1,1,0,0,0,0,0,1,0,1,1,0,0,0,0,1,0,0,1,1,1,0,0,0,0,0,0,0,0,0,1,1,0,
%U A113998 0,0,0,0,1,0,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,1,0,0,0,0,1,1
%N A113998 Reverse of triangle A051731.
%C A113998 Row sums are A000005. Diagonal sums are A001227 (?). Row k corresponds to A113999(k).
%F A113998 Sum_{k, 1<=k<=n} k*T(n,k)=A081307(n) - _Philippe Deléham_, Feb 03 2007
%e A113998 Triangle begins
%e A113998 1;
%e A113998 1,1;
%e A113998 1,0,1;
%e A113998 1,0,1,1;
%e A113998 1,0,0,0,1;
%e A113998 1,0,0,1,1,1;
%e A113998 1,0,0,0,0,0,1;
%e A113998 1,0,0,0,1,0,1,1;
%K A113998 nonn,tabl
%O A113998 1,1
%A A113998 _Paul Barry_, Nov 12 2005