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 A117268 #7 Apr 25 2016 12:17:38 %S A117268 1,1,1,2,1,2,4,2,3,5,7,4,6,9,14,13,7,11,17,26,40,24,13,20,31,48,74, %T A117268 114,44,24,37,57,88,136,210,324,81,44,68,105,162,250,386,596,920 %N A117268 Triangle, binomial transform of the tribonacci sequence. %C A117268 Leftmost column of the triangle = the tribonacci sequence A000073. %C A117268 Rightmost diagonal of the triangle = A117189. %F A117268 Difference rows of A117267 become rows of A117268 %e A117268 Taking difference rows of A117267: (1; 1, 2; 2, 3, 5; 4, 6, 9, 14;...), we get A117268: %e A117268 1; %e A117268 1, 1; %e A117268 2, 1, 2; %e A117268 4, 2, 3, 5; %e A117268 7, 4, 6, 9, 14; %e A117268 13, 7, 11, 17, 26, 40; %e A117268 24, 13, 20, 31, 48, 74, 114; %e A117268 ... %Y A117268 Cf. A117267, A117189 (row sums), A000073. %K A117268 nonn,tabl %O A117268 1,4 %A A117268 _Gary W. Adamson_, Mar 05 2006