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 A101038 #3 Mar 30 2012 18:59:02
%S A101038 1,-3,1,4,-3,1,-4,4,-3,1,4,-4,4,-3,1,-4,4,-4,4,-3,1,4,-4,4,-4,4,-3,1,
%T A101038 -4,4,-4,4,-4,4,-3,1,4,-4,4,-4,4,-4,4,-3,1,-4,4,-4,4,-4,4,-4,4,-3,1,4,
%U A101038 -4,4,-4,4,-4,4,-4,4,-3,1,-4,4,-4,4,-4,4,-4,4,-4,4,-3,1,4,-4,4,-4
%N A101038 Inverse to sequence matrix for odd numbers.
%C A101038 Riordan matrix ((1-x)^2/(1+x), x). Inverse matrix is A099375 Row sums yield (-1)^n*A040000. Diagonal sums are (-1)(2n+1)=(-1)^n*A005408.
%F A101038 Number triangle T(n, k)=if(k<=n, 4(-1)^(n-k)-3*0^(n-k)+C(1, n-k)-C(0, n-k), 0)
%e A101038 Rows begin {1}, {-3,1}, {4,-3,1}, {-4,4,-3,1}, {4,-4,4,-3,1},...
%K A101038 easy,sign,tabl
%O A101038 0,2
%A A101038 _Paul Barry_, Jan 22 2005