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 A224198 #8 Jan 20 2024 13:37:56 %S A224198 4,160,16060,2411246,451319098,96914926654,22835261226043, %T A224198 5750097317505437,1521786116504544601,418628292901694453231, %U A224198 118789461093773656747975,34580941641153629118242103 %N A224198 Number of n X n 0..3 arrays with rows unimodal and antidiagonals nondecreasing. %C A224198 Diagonal of A224204. %H A224198 R. H. Hardin, <a href="/A224198/b224198.txt">Table of n, a(n) for n = 1..17</a> %e A224198 Some solutions for n=3 %e A224198 ..1..3..3....1..0..0....3..0..0....0..3..1....1..1..1....1..3..1....0..0..1 %e A224198 ..3..3..1....1..0..0....1..1..1....3..2..1....3..1..0....3..2..0....3..2..1 %e A224198 ..3..2..0....0..3..2....1..1..2....3..2..2....2..3..0....3..3..1....2..3..1 %Y A224198 Cf. A224204. %K A224198 nonn %O A224198 1,1 %A A224198 _R. H. Hardin_, Apr 01 2013