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 A127778 #5 Mar 30 2012 17:25:18 %S A127778 1,1,6,1,6,18,1,6,18,40,1,6,18,40,75,1,6,18,40,75,126,1,6,18,40,75, %T A127778 126,196,1,6,18,40,75,126,196,288 %N A127778 Triangle T(n,k) = A002411(k) read by rows. %F A127778 Equals the matrix product A002260 * A127773 as infinite lower triangular matrices. %e A127778 First few rows of the triangle are: %e A127778 1; %e A127778 1, 6; %e A127778 1, 6, 18; %e A127778 1, 6, 18, 40; %e A127778 1, 6, 18, 40, 75; %e A127778 ... %Y A127778 Cf. A002411, A001296 (row sums), A127773, A002260, A127777. %K A127778 nonn,easy,tabl %O A127778 1,3 %A A127778 _Gary W. Adamson_, Jan 28 2007