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 A224171 #9 Mar 18 2025 20:55:26 %S A224171 610,52591,1253770,15925611,143558572,1038484760,6360047093, %T A224171 33901838632,160168789130,680269560125,2628521964178,9335303943077, %U A224171 30746296739238,94635507313740,274045375789233,750986358734170,1957473961121912,4874764357410065,11644219526875714 %N A224171 Number of n X 6 0..3 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing. %H A224171 R. H. Hardin, <a href="/A224171/b224171.txt">Table of n, a(n) for n = 1..210</a> %F A224171 Empirical: a(n) = (42587101/1600593426432000)*n^18 + (83940121/177843714048000)*n^17 + (308341547/31384184832000)*n^16 + (23656547/201180672000)*n^15 + (19255277651/15692092416000)*n^14 + (8091120109/747242496000)*n^13 + (255948441937/3621252096000)*n^12 + (100806994639/201180672000)*n^11 + (447955595981/219469824000)*n^10 + (936116756663/73156608000)*n^9 + (89792239149827/2414168064000)*n^8 + (167645449561/1026432000)*n^7 + (5108091310778959/11769069312000)*n^6 - (433115879452601/217945728000)*n^5 + (6324467156344901/653837184000)*n^4 - (35759831917609/698544000)*n^3 + (1815894225096923/15437822400)*n^2 + (1874103131609/6126120)*n - 1349188 for n>9. %e A224171 Some solutions for n=3: %e A224171 ..0..0..1..1..2..3....0..0..1..1..1..0....0..0..0..1..2..1....0..0..1..1..0..0 %e A224171 ..0..0..1..1..2..3....0..2..3..2..2..0....0..0..0..3..3..1....0..0..1..2..2..0 %e A224171 ..0..0..1..2..3..3....0..2..3..3..2..0....0..0..1..3..3..3....0..2..2..2..2..2 %Y A224171 Column 6 of A224173. %K A224171 nonn %O A224171 1,1 %A A224171 _R. H. Hardin_, Mar 31 2013 %E A224171 Name corrected by _Andrew Howroyd_, Mar 18 2025