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 A107727 #3 Mar 30 2012 18:36:46
%S A107727 1,-1,1,-3,-2,1,-21,-7,-3,1,-219,-53,-13,-4,1,-2973,-583,-115,-21,-5,
%T A107727 1,-49323,-8249,-1437,-217,-31,-6,1,-964173,-141655,-22715,-3101,-369,
%U A107727 -43,-7,1,-21680571,-2853185,-430877,-55251,-5975,-581,-57,-8,1,-551173053,-65887783,-9505707,-1168349,-119137
%N A107727 Matrix inverse of A107719.
%C A107727 Matrix square is A107728. Matrix cube is A107726. Column 0 is negative A107716 shift right.
%e A107727 Triangle begins:
%e A107727 1;
%e A107727 -1,1;
%e A107727 -3,-2,1;
%e A107727 -21,-7,-3,1;
%e A107727 -219,-53,-13,-4,1;
%e A107727 -2973,-583,-115,-21,-5,1;
%e A107727 -49323,-8249,-1437,-217,-31,-6,1;
%e A107727 -964173,-141655,-22715,-3101,-369,-43,-7,1; ...
%o A107727 (PARI) {T(n,k)=local(L,N,M=matrix(n+1,n+1,m,j,if(m>=j,if(m==j,1,if(m==j+1,-3*j, polcoeff(1/sum(i=0,m-j,prod(r=0,i-1,3*r+1)*x^i)+O(x^m),m-j)))))^-1); L=sum(i=1,#M,(M^0-M)^i/i)/3;N=sum(i=0,#L,L^i/i!); return(if(n<0,0,N[n+1,k+1]))}
%Y A107727 Cf. A107716, A107719, A107726, A107728.
%K A107727 sign,tabl
%O A107727 0,4
%A A107727 _Paul D. Hanna_, May 30 2005