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 A128134 #26 Feb 15 2022 02:08:39 %S A128134 1,1,2,2,5,3,3,10,11,4,4,17,27,19,5,5,26,54,56,29,6,6,37,95,130,100, %T A128134 41,7,7,50,153,260,265,162,55,8,8,65,231,469,595,483,245,71,9,9,82, %U A128134 332,784,1190,1204,812,352,89,10 %N A128134 A128132 * A007318. %C A128134 A007318 * A128132 = A128133. Row sums = A128135: (1, 3, 10, 28, 72, 176, ...). %F A128134 A128132 * A007318 as infinite lower triangular matrices (assuming the top of the Pascal triangle A007318 is shifted from (0,0) to (1,1)). %F A128134 From _Petros Hadjicostas_, Jul 26 2020: (Start) %F A128134 T(n,k) = n*binomial(n-1, k-1) - binomial(n-2, k-1)*[n <> k] for 1 <= k <= n, where [ ] is the Iverson bracket. %F A128134 Bivariate o.g.f.: x*y*(1 - x + x^2*(1 + y))/(1 - x*(1 + y))^2. %F A128134 T(n,k) = T(n-1,k) + T(n-1,k-1) + binomial(n-1,k-1) for 2 <= k <= n with (n,k) <> (2,2). %F A128134 T(n,k) = 2*T(n-1,k) - T(n-2,k) - T(n-2,k-2) + 2*T(n-1,k-1) - 2*T(n-2,k-1) for 3 <= k <= n with (n,k) <> (3,3). %F A128134 T(n,1) = n - 1 for n >= 2. %F A128134 T(n,2) = A002522(n-1) for n >= 2. %F A128134 T(n,3) = A164845(n-3) for n >= 3. %F A128134 T(n,4) = A332697(n-3) for n >= 4. %F A128134 T(n,n) = n for n >= 1. %F A128134 T(n,n-1) = A028387(n-2) for n >= 2. (End) %e A128134 Triangle T(n,k) (with rows n >= 1 and columns k = 1..n) begins: %e A128134 1; %e A128134 1, 2; %e A128134 2, 5, 3; %e A128134 3, 10, 11, 4; %e A128134 4, 17, 27, 19, 5; %e A128134 5, 26, 54, 56, 29, 6; %e A128134 6, 37, 95, 130, 100, 41, 7; %e A128134 ... %Y A128134 Cf. A002522, A007318, A028387, A128132, A128133, A128135, A164845, A332697. %K A128134 nonn,tabl %O A128134 1,3 %A A128134 _Gary W. Adamson_, Feb 15 2007