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 A269743 #17 Feb 22 2020 19:59:52 %S A269743 1,1,1,1,1,1,4,11,23,11,4,1,1,11,72,325,595,595,325,72,11,1,1,26,367, %T A269743 3368,14679,34679,46800,34679,14679,3368,367,26,1,1,57,1630,28819, %U A269743 253247,1212440,3382133,5588593,5588593,3382133,1212440,253247,28819,1630,57,1 %N A269743 Triangle of generalized Eulerian numbers T(n,k) = <n,k>_3 read by rows, n >= 1, 0 <= k <= 3*(n-1). %C A269743 T(n,k) is the number of nonnegative integer n X n matrices with every row and column sum 3 and sum of entries below the main diagonal k. The case when every row and column sum is 1 is given by the Eulerian numbers (A008292). - _Andrew Howroyd_, Feb 22 2020 %H A269743 Andrew Howroyd, <a href="/A269743/b269743.txt">Table of n, a(n) for n = 1..925</a> (first 25 rows) %H A269743 Esther M. Banaian, <a href="http://digitalcommons.csbsju.edu/honors_thesis/24">Generalized Eulerian Numbers and Multiplex Juggling Sequences</a>, (2016). All College Thesis Program. Paper 24. %H A269743 E. Banaian, S. Butler, C. Cox, J. Davis, J. Landgraf and S. Ponce, <a href="http://arxiv.org/abs/1508.03673">A generalization of Eulerian numbers via rook placements</a>, arXiv:1508.03673 [math.CO], 2015. %H A269743 Andrew Howroyd, <a href="/A269743/a269743.txt">PARI Program</a> %e A269743 Triangle begins: %e A269743 1, %e A269743 1,1,1,1, %e A269743 1,4,11,23,11,4,1, %e A269743 1,11,72,325,595,595,325,72,11,1, %e A269743 ... %o A269743 (PARI) \\ See link. - _Andrew Howroyd_, Feb 22 2020 %Y A269743 Row sums are A001500. %Y A269743 Columns k=0..4 are A000012, A000295, A260585, A260727, A260583. %Y A269743 Cf. A008292, A269742, A269744. %K A269743 nonn,tabf %O A269743 1,7 %A A269743 _N. J. A. Sloane_, Mar 16 2016 %E A269743 Terms a(23) and beyond from _Andrew Howroyd_, Feb 22 2020