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 A224193 #6 Jul 23 2025 05:02:18 %S A224193 28,784,13524,163746,1519738,11444292,72710554,400958714,1960596602, %T A224193 8643660124,34817290272,129528551708,449030731802,1461369918218, %U A224193 4493166765659,13121663640985,36566337458326,97628603745396 %N A224193 Number of 6Xn 0..2 arrays with rows unimodal and columns nondecreasing. %C A224193 Row 6 of A224190 %H A224193 R. H. Hardin, <a href="/A224193/b224193.txt">Table of n, a(n) for n = 1..210</a> %F A224193 Empirical: a(n) = (1/35608838483312640000)*n^24 + (1/228261785149440000)*n^23 + (2993/8515157028618240000)*n^22 + (1189/64508765368320000)*n^21 + (112787/162193467211776000)*n^20 + (4033303/202741834014720000)*n^19 + (100023181/224083079700480000)*n^18 + (75069509/9336794987520000)*n^17 + (1246517053/10545086103552000)*n^16 + (6306246257/4393785876480000)*n^15 + (18213412351/1255367393280000)*n^14 + (38516770459/313841848320000)*n^13 + (9185104716379/10545086103552000)*n^12 + (1753572682469/337983528960000)*n^11 + (42653443424521/1647669703680000)*n^10 + (118327836601829/1098446469120000)*n^9 + (1768182454793/4763670912000)*n^8 + (698418986666497/666913927680000)*n^7 + (26428459959973901/11087444047680000)*n^6 + (31671555902461499/7391629365120000)*n^5 + (14625059352544909/2463876455040000)*n^4 + (438413487383/71292721500)*n^3 + (10755031442327/2248776129600)*n^2 + (2550558151/1338557220)*n + 1 %e A224193 Some solutions for n=3 %e A224193 ..0..1..1....0..1..0....0..0..0....0..1..1....0..0..0....0..0..0....0..1..0 %e A224193 ..1..1..1....0..1..0....1..0..0....1..1..1....0..0..0....0..1..0....0..2..0 %e A224193 ..1..2..1....1..1..1....1..0..0....2..1..1....0..0..0....1..1..1....1..2..1 %e A224193 ..1..2..1....1..2..2....1..1..1....2..2..1....1..2..1....2..1..1....1..2..1 %e A224193 ..2..2..1....2..2..2....2..1..1....2..2..2....1..2..1....2..2..2....2..2..1 %e A224193 ..2..2..1....2..2..2....2..2..2....2..2..2....1..2..2....2..2..2....2..2..1 %K A224193 nonn %O A224193 1,1 %A A224193 _R. H. Hardin_ Apr 01 2013