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 A224016 #6 Jul 23 2025 04:51:42 %S A224016 729,46656,534352,3094127,13275381,47735665,150787422,430109607, %T A224016 1128769430,2762176256,6366017979,13926332849,29098170483,58367669325, %U A224016 112877225362,211218704199,383609908528,678009948228,1168905645807 %N A224016 Number of 6Xn 0..2 arrays with rows nondecreasing and antidiagonals unimodal. %C A224016 Row 6 of A224012 %H A224016 R. H. Hardin, <a href="/A224016/b224016.txt">Table of n, a(n) for n = 1..210</a> %F A224016 Empirical: a(n) = (761/8553600)*n^12 + (811/302400)*n^11 + (4879/97200)*n^10 + (230029/362880)*n^9 + (10666727/1814400)*n^8 + (6162019/151200)*n^7 + (76144063/388800)*n^6 + (1772311/2688)*n^5 + (230134279/194400)*n^4 + (14927389/453600)*n^3 - (7982908/51975)*n^2 + (2910398/315)*n + 7207 for n>4 %e A224016 Some solutions for n=3 %e A224016 ..0..0..1....0..0..1....0..0..1....0..0..1....0..0..0....0..0..1....0..0..0 %e A224016 ..0..0..1....0..1..1....0..1..1....0..0..0....2..2..2....1..1..1....0..0..0 %e A224016 ..0..1..2....0..2..2....1..2..2....0..0..0....0..0..2....1..1..2....0..1..2 %e A224016 ..0..2..2....0..1..1....2..2..2....0..0..1....0..1..2....0..1..2....1..2..2 %e A224016 ..2..2..2....1..1..2....0..2..2....2..2..2....0..2..2....1..2..2....0..0..1 %e A224016 ..1..1..2....0..1..1....1..1..1....0..2..2....0..2..2....2..2..2....0..2..2 %K A224016 nonn %O A224016 1,1 %A A224016 _R. H. Hardin_ Mar 30 2013