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 A199324 #17 Feb 22 2013 14:40:20
%S A199324 1,-1,1,0,-1,1,1,-1,-1,1,-1,3,-2,-1,1,0,-2,5,-3,-1,1,1,-2,-2,7,-4,-1,
%T A199324 1,-1,5,-7,-1,9,-5,-1,1,0,-3,12,-15,1,11,-6,-1,1,1,-3,-3,21,-26,4,13,
%U A199324 -7,-1,1,-1,7,-15,3,31,-40,8,15,-8,-1,1,0,-4,22,-42
%N A199324 Triangle T(n,k), read by rows, given by (-1,1,-1,0,0,0,0,0,0,0,...) DELTA (1,0,0,0,0,0,0,0,0,0,...) where DELTA is the operator defined in A084938.
%F A199324 T(n,k)=T(n-1,k-1)+T(n-2,k-1)-T(n-1,k)-T(n-2,k), T(0,0)=1.
%F A199324 G.f.: 1/(1-(y-1)*x-(y-1)*x^2).
%F A199324 Sum_{k, 0<=k<=n}T(n,k)*x^k = A000748(n), A108520(n), A049347(n), A000007(n), A000045(n+1), A002605(n+1), A030195(n+1), A057087(n), A057088(n), A057089(n), A057090(n), A057091(n), A057092(n), A057093(n) for x = -2,-1,0,1,2,3,4,5,6,7,8,9,10,11 respectively.
%e A199324 Triangle begins :
%e A199324 1
%e A199324 -1, 1
%e A199324 0, -1, 1
%e A199324 1, -1, -1, 1
%e A199324 -1, 3, -2, -1, 1
%e A199324 0, -2, 5, -3, -1, 1
%e A199324 1, -2, -2, 7, -4, -1, 1
%e A199324 -1, 5, -7, -1, 9, -5, -1, 1
%Y A199324 Cf. A026729, A063967, A129267, A176971 (diagonals sums).
%K A199324 sign,tabl
%O A199324 0,12
%A A199324 _Philippe Deléham_, Nov 12 2011