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 A223790 #6 Jun 09 2023 22:57:17 %S A223790 27,729,8635,62365,334230,1455816,5425943,17876443,53233499,145612231, %T A223790 370377451,884526855,1998822498,4301425736,8862298953,17560558967, %U A223790 33594162385,62253768525,112071502931,196491932081,336258321854 %N A223790 Number of 3 X n 0..2 arrays with rows, diagonals and antidiagonals unimodal. %C A223790 Row 3 of A223789. %H A223790 R. H. Hardin, <a href="/A223790/b223790.txt">Table of n, a(n) for n = 1..210</a> %F A223790 Empirical: a(n) = (5051/239500800)*n^12 + (9539/39916800)*n^11 + (86021/21772800)*n^10 + (2861/103680)*n^9 + (1419461/7257600)*n^8 + (453883/403200)*n^7 + (30663023/21772800)*n^6 + (10887469/725760)*n^5 - (167107181/5443200)*n^4 + (16805993/129600)*n^3 - (226950043/831600)*n^2 + (1171756/3465)*n - 185 for n>1. %e A223790 Some solutions for n=3 %e A223790 ..2..1..0....1..2..0....0..1..1....2..2..0....1..2..2....0..0..2....1..2..1 %e A223790 ..1..1..1....1..2..0....0..1..1....0..0..1....2..2..1....0..2..1....1..2..1 %e A223790 ..1..2..0....1..1..0....2..2..0....0..1..0....1..2..0....1..2..2....1..1..0 %Y A223790 Cf. A223789. %K A223790 nonn %O A223790 1,1 %A A223790 _R. H. Hardin_, Mar 27 2013