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 A223916 #6 Jul 23 2025 04:38:46 %S A223916 148,4102,45988,323394,1721356,7526024,28247478,93683295,280338123, %T A223916 769012348,1958026231,4673735444,10543684618,22631328296,46477583300, %U A223916 91756934105,174838318505,322648096420,578369211133,1009683032422 %N A223916 Number of nX6 0..2 arrays with rows and antidiagonals unimodal and columns nondecreasing. %C A223916 Column 6 of A223918 %H A223916 R. H. Hardin, <a href="/A223916/b223916.txt">Table of n, a(n) for n = 1..210</a> %F A223916 Empirical: a(n) = (761/8553600)*n^12 + (761/475200)*n^11 + (21583/1088640)*n^10 + (458/2835)*n^9 + (1760837/1814400)*n^8 + (1346021/302400)*n^7 + (430403/31104)*n^6 + (19199/480)*n^5 + (88406683/1360800)*n^4 + (13099679/226800)*n^3 - (3421811/41580)*n^2 - (5265011/13860)*n + 389 for n>3 %e A223916 Some solutions for n=3 %e A223916 ..1..1..1..0..0..0....1..1..1..1..1..0....0..0..1..1..0..0....0..1..0..0..0..0 %e A223916 ..1..1..1..1..0..0....1..1..1..1..2..1....0..1..2..2..2..1....1..1..1..0..0..0 %e A223916 ..1..1..2..2..2..1....1..2..2..2..2..1....1..1..2..2..2..1....1..1..1..2..2..2 %K A223916 nonn %O A223916 1,1 %A A223916 _R. H. Hardin_ Mar 29 2013