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 A223994 #6 Jul 23 2025 04:47:42 %S A223994 10,76,476,2980,18672,117386,739672,4664776,29428242,185670484, %T A223994 1171477424,7391425016,46636189140,294251036912,1856576835280, %U A223994 11714070469768,73909919072136,466334575535548,2942337620960936 %N A223994 Number of nX3 0..2 arrays with antidiagonals unimodal and rows and diagonals nondecreasing. %C A223994 Column 3 of A223999 %H A223994 R. H. Hardin, <a href="/A223994/b223994.txt">Table of n, a(n) for n = 1..210</a> %F A223994 Empirical: a(n) = 10*a(n-1) -24*a(n-2) -2*a(n-3) +30*a(n-4) +96*a(n-5) -150*a(n-6) -108*a(n-7) +48*a(n-8) +270*a(n-9) %e A223994 Some solutions for n=3 %e A223994 ..2..2..2....1..1..2....0..0..0....0..0..2....0..1..1....0..0..0....0..1..1 %e A223994 ..2..2..2....1..1..2....0..0..2....1..2..2....1..2..2....0..0..1....0..0..2 %e A223994 ..0..2..2....0..2..2....1..1..2....0..1..2....1..2..2....1..1..2....0..0..2 %K A223994 nonn %O A223994 1,1 %A A223994 _R. H. Hardin_ Mar 30 2013