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 A124377 #5 Jan 12 2014 11:25:41
%S A124377 1,1,1,2,0,1,3,2,-1,1,5,1,3,-2,1,8,4,-2,5,-3,1,13,4,6,-7,8,-4,1,21,9,
%T A124377 -2,13,-15,12,-5,1,34,12,11,-15,28,-27,17,-6,1,55,22,1,26,-43,55,-44,
%U A124377 23,-7,1,89,33,21
%N A124377 Riordan array (1/(1-x-x^2),x/(1+x)).
%C A124377 First column is F(n+1). Second column is A008346. Row sums are F(n+2). Diagonal sums are A094966(n+1). Product of A007318 and A124377 is the Riordan array ((1-x)/(1-3x+x^2),x), the sequence array for F(2n+1).
%F A124377 Number triangle T(n,k)=sum{j=0..n-k, C(j-k,n-k-j)}*[k<=n]
%F A124377 T(n,k)=T(n-1,k-1)+2*T(n-2,k)-T(n-2,k-1)+T(n-3,k)-T(n-3,k-1), T(0,0)=T(1,0)=T(1,1)=1, T(n,k)=0 if k<0 or if k>n. - _Philippe Deléham_, Jan 12 2014
%F A124377 T(n,0)=A000045(n+1), T(n,n)=1, T(n,k)=T(n-1,k-1)-T(n-1,k) for 0<k<n. - _Philippe Deléham_, Jan 12 2014
%e A124377 Triangle begins
%e A124377 1,
%e A124377 1, 1,
%e A124377 2, 0, 1,
%e A124377 3, 2, -1, 1,
%e A124377 5, 1, 3, -2, 1,
%e A124377 8, 4, -2, 5, -3, 1,
%e A124377 13, 4, 6, -7, 8, -4, 1,
%e A124377 21, 9, -2, 13, -15, 12, -5, 1
%Y A124377 Cf. A000045
%K A124377 easy,sign,tabl
%O A124377 0,4
%A A124377 _Paul Barry_, Oct 29 2006