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 A224394 #6 Jul 23 2025 05:09:15 %S A224394 1024,100000,1268572,8573507,45648753,211856287,882833522,3343528551, %T A224394 11604617405,37199618077,110964317169,310166468938,817551602005, %U A224394 2043560704475,4868244723248,11101332102787,24326305539913 %N A224394 Number of 5Xn 0..3 arrays with diagonals and antidiagonals unimodal and rows nondecreasing. %C A224394 Row 5 of A224391 %H A224394 R. H. Hardin, <a href="/A224394/b224394.txt">Table of n, a(n) for n = 1..210</a> %F A224394 Empirical: a(n) = (769/444787200)*n^15 + (348923/10897286400)*n^14 + (1834741/3113510400)*n^13 + (1653961/239500800)*n^12 + (15881209/239500800)*n^11 + (3185767/4354560)*n^10 + (6331231/21772800)*n^9 + (8051546371/152409600)*n^8 - (92949613/680400)*n^7 + (29776075747/21772800)*n^6 - (235108166129/119750400)*n^5 + (1142919607439/59875200)*n^4 - (2395878032771/43243200)*n^3 + (4577919285997/37837800)*n^2 - (3999067013/10010)*n + 824171 for n>7 %e A224394 Some solutions for n=3 %e A224394 ..0..0..0....0..0..2....0..0..2....0..0..2....0..0..2....0..2..2....0..2..2 %e A224394 ..2..2..3....1..2..2....1..2..2....0..2..2....1..2..3....1..2..3....1..2..3 %e A224394 ..2..2..2....1..1..2....1..2..2....0..2..3....2..3..3....1..2..3....0..2..2 %e A224394 ..1..2..2....0..2..2....0..2..3....0..2..2....2..3..3....1..1..2....0..2..3 %e A224394 ..1..1..2....1..3..3....2..2..2....1..3..3....2..3..3....0..1..3....0..2..3 %K A224394 nonn %O A224394 1,1 %A A224394 _R. H. Hardin_ Apr 05 2013