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 A373426 #6 Jun 13 2024 08:31:37 %S A373426 1,0,1,0,2,1,0,6,12,7,1,0,24,108,144,73,15,1,0,120,1080,2640,2660, %T A373426 1221,267,27,1,0,720,11880,48720,82980,67350,28321,6344,751,44,1,0, %U A373426 5040,146160,955080,2529240,3262350,2245782,870283,195074,25267,1831,68,1 %N A373426 Triangle read by rows: Coefficients of the polynomials L(n, x) * EZ(n, x), where L denote the unsigned Lah polynomials and EZ the Eulerian zig-zag polynomials A205497. %H A373426 Peter Luschny, <a href="/A373426/a373426.png">Illustrating the polynomials</a>. %e A373426 Tracing the computation: %e A373426 0: [1] * [1] = [1] %e A373426 1: [1] * [0, 1] = [0, 1] %e A373426 2: [1] * [0, 2, 1] = [0, 2, 1] %e A373426 3: [1, 1] * [0, 6, 6, 1] = [0, 6, 12, 7, 1] %e A373426 4: [1, 3, 1] * [0, 24, 36, 12, 1] = [0, 24, 108, 144, 73, 15, 1] %p A373426 # Using function EZP from A373432. %p A373426 EZP((n, k) -> ifelse(n=k, 1, binomial(n-1, k-1)*n!/k!), 7); %Y A373426 Cf. A271703 (Lah), A205497 (zig-zag Eulerian), A373425 (row sums). %K A373426 nonn,tabf %O A373426 0,5 %A A373426 _Peter Luschny_, Jun 07 2024