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 A223922 #6 Jul 23 2025 04:39:19 %S A223922 21,441,5548,48182,319156,1721356,7906972,31947798,116289938, %T A223922 388293504,1205901516,3520937666,9746278721,25746339006,65246565981, %U A223922 159287861727,375892787585,859832700375,1910938878762,4134527627922,8723666100444 %N A223922 Number of 5Xn 0..2 arrays with rows and antidiagonals unimodal and columns nondecreasing. %C A223922 Row 5 of A223918 %H A223922 R. H. Hardin, <a href="/A223922/b223922.txt">Table of n, a(n) for n = 1..210</a> %F A223922 Empirical: a(n) = (1/1379196149760000)*n^20 + (1/27583922995200)*n^19 + (67/43553562624000)*n^18 + (2203/50812489728000)*n^17 + (35813/34871316480000)*n^16 + (4723/232475443200)*n^15 + (2458331/6974263296000)*n^14 + (8083259/1494484992000)*n^13 + (508218079/6897623040000)*n^12 + (34902853/45984153600)*n^11 + (6145973531/1072963584000)*n^10 + (1981076359/59609088000)*n^9 + (981368164559/6538371840000)*n^8 + (7803754241/14944849920)*n^7 + (1568765927873/1120863744000)*n^6 + (533988456371/186810624000)*n^5 + (40563025942379/9262693440000)*n^4 + (15131959121/3087564480)*n^3 + (22082097187/5431826400)*n^2 + (196063237/116396280)*n + 1 %e A223922 Some solutions for n=3 %e A223922 ..0..0..0....0..0..0....2..0..0....0..1..0....1..0..0....2..2..1....0..0..1 %e A223922 ..1..2..0....0..0..1....2..0..0....1..1..0....1..0..0....2..2..2....0..0..1 %e A223922 ..1..2..1....0..1..1....2..1..0....2..1..0....1..2..0....2..2..2....0..0..1 %e A223922 ..1..2..2....2..1..1....2..1..0....2..1..0....2..2..2....2..2..2....0..1..1 %e A223922 ..2..2..2....2..2..2....2..1..1....2..2..0....2..2..2....2..2..2....0..2..1 %K A223922 nonn %O A223922 1,1 %A A223922 _R. H. Hardin_ Mar 29 2013