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 A123262 #6 Sep 08 2013 13:30:57
%S A123262 0,0,1,0,0,1,0,0,0,2,0,0,0,1,3,0,0,0,0,2,5,0,0,0,0,0,5,8,0,0,0,0,0,1,
%T A123262 10,13,0,0,0,0,0,0,3,20,21,0,0,0,0,0,0,0,9,38,34,0,0,0,0,0,0,0,1,22,
%U A123262 71,55,0,0,0,0,0,0,0,0,4,51,130,89,0,0,0,0,0,0,0,0,0,14,111,235,144
%N A123262 Fibonacci-tribonacci triangle.
%C A123262 Or, skew Jacobsthal-Lucas triangle, read by rows.
%F A123262 T(n,k)=T(n-1,k-1)+T(n-2,k-2)+T(n-3,k-2), T(n,0)=0, T(1,1)=1, T(n,k)=0 if k<0 or if k>n . T(n,n)= Fibonacci(n)=A000045(n) . Sum_{k, 0<=k<=n}T(n,k)=A000073(n+1), tribonacci numbers . Sum_{n, n>=k}T(n,k)=A001045(k), Jacobsthal sequence.
%e A123262 Triangle begins:
%e A123262 .0;
%e A123262 .0, 1;
%e A123262 .0, 0, 1;
%e A123262 .0, 0, 0, 2;
%e A123262 .0, 0, 0, 1, 3;
%e A123262 .0, 0, 0, 0, 2, 5;
%e A123262 .0, 0, 0, 0, 0, 5, 8;
%e A123262 .0, 0, 0, 0, 0, 1, 10, 13;
%e A123262 .0, 0, 0, 0, 0, 0, 3, 20, 21;
%e A123262 .0, 0, 0, 0, 0, 0, 0, 9, 38, 34;
%e A123262 .0, 0, 0, 0, 0, 0, 0, 1, 22, 71, 55;
%e A123262 .0, 0, 0, 0, 0, 0, 0, 0, 4, 51, 130, 89;
%e A123262 .0, 0, 0, 0, 0, 0, 0, 0, 0, 14, 111, 235, 144;
%Y A123262 Cf. A037027.
%K A123262 nonn,tabl
%O A123262 0,10
%A A123262 _Philippe Deléham_, Nov 06 2006