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 A321967 #19 Dec 31 2018 04:13:58 %S A321967 1,0,1,0,-4,11,0,15,-156,302,0,-56,1596,-9528,15619,0,210,-14400, %T A321967 193185,-882340,1310354,0,-792,122265,-3213760,30042672,-116857368, %U A321967 162512286,0,3003,-1005004,47887840,-802069632,6034981134,-21078701112,27971176092 %N A321967 Triangle read by rows, T(n,k) = binomial(-k-n-1, -2*n-1)*E1(k+n, n), E1 the Eulerian numbers A173018, for n >= 0 and 0 <= k <= n. %e A321967 Triangle starts: %e A321967 1; %e A321967 0, 1; %e A321967 0, -4, 11; %e A321967 0, 15, -156, 302; %e A321967 0, -56, 1596, -9528, 15619; %e A321967 0, 210, -14400, 193185, -882340, 1310354; %e A321967 0, -792, 122265, -3213760, 30042672, -116857368, 162512286; %p A321967 T := (n, k) -> binomial(-k-n-1, -2*n-1)*combinat:-eulerian1(k+n, n): %p A321967 for n from 0 to 7 do seq(T(n,k), k=0..n) od; %t A321967 E1[n_ /; n >= 0, 0] = 1; E1[n_, k_] /; k < 0 || k > n = 0; %t A321967 E1[n_, k_] := E1[n, k] = (n - k) E1[n - 1, k - 1] + (k + 1) E1[n - 1, k]; %t A321967 T[n_, k_] := Binomial[-k - n - 1, -2 n - 1] E1[n + k, n]; %t A321967 Table[T[n, k], {n, 0, 7}, {k, 0, n}] // Flatten %t A321967 (* _Jean-François Alcover_, Dec 30 2018 *) %Y A321967 Row sums give A320337. %Y A321967 Cf. A046739, A180056 (main diagonal), A271697, A001791. %K A321967 sign,tabl %O A321967 0,5 %A A321967 _Peter Luschny_, Dec 18 2018