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 A223890 #6 May 27 2021 15:12:55 %S A223890 22,564,11264,187103,2719602,35688774,432076735,4902528769, %T A223890 52736915601,542569977315,5375623914286,51570049073953, %U A223890 481136370463155,4381314203869479,39057034725462456,341691760691655645 %N A223890 Number of n X 3 0..2 arrays with row sums and column sums unimodal. %C A223890 Column 3 of A223892. %H A223890 R. H. Hardin, <a href="/A223890/b223890.txt">Table of n, a(n) for n = 1..51</a> %e A223890 Some solutions for n=3 %e A223890 ..2..2..0....2..2..1....0..2..1....1..2..0....0..0..1....2..1..1....0..0..0 %e A223890 ..0..2..2....1..1..1....2..1..1....2..1..0....0..1..2....2..2..2....0..1..0 %e A223890 ..2..0..2....0..2..1....1..2..0....1..0..1....0..2..2....0..1..0....2..1..0 %Y A223890 Cf. A223892. %K A223890 nonn %O A223890 1,1 %A A223890 _R. H. Hardin_ Mar 28 2013