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 A128444 #2 Mar 30 2012 18:57:10 %S A128444 1,3,3,5,6,5,6,9,10,9,8,12,15,18,15,10,15,20,27,31,27,12,18,25,36,46, %T A128444 54,46,13,21,31,45,62,81,93,81,15,24,36,54,77,108,140,162,140,17,27, %U A128444 41,63,93,135,187,243,280,243,19,30,46,72,109,162,233,324,420,486,420,20,33 %N A128444 Array T by antidiagonals: T(n,k)=Floor(k*3^(n/2)). %C A128444 Row 1 = A022838; Row 2 = A008585; Column 1 = A017913; T(n,n) = A128443(n). %e A128444 Northwest corner: %e A128444 1 3 5 6 8 %e A128444 3 6 9 12 15 %e A128444 5 10 15 20 25 %e A128444 9 18 27 36 45 %Y A128444 Cf. A128443. %K A128444 nonn,tabl %O A128444 1,2 %A A128444 _Clark Kimberling_, Mar 03 2007