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 A223929 #6 Jul 23 2025 04:39:43 %S A223929 46,698,4498,21334,86439,316136,1065625,3337831,9773219,26903878, %T A223929 70024867,173255292,409514526,928832014,2029581476,4287303027, %U A223929 8781854785,17488776976,33939319272,64311697250,119202262153,216450903569 %N A223929 Number of nX4 0..2 arrays with rows, columns and antidiagonals unimodal and diagonals nondecreasing. %C A223929 Column 4 of A223933 %H A223929 R. H. Hardin, <a href="/A223929/b223929.txt">Table of n, a(n) for n = 1..210</a> %F A223929 Empirical: a(n) = (1/106748928000)*n^16 + (1/13343616000)*n^15 + (1/116756640)*n^14 + (4003/37362124800)*n^13 + (97199/28740096000)*n^12 + (670871/14370048000)*n^11 + (94057/130636800)*n^10 - (113957/261273600)*n^9 + (565001317/5225472000)*n^8 - (887457691/1306368000)*n^7 + (3190047029/359251200)*n^6 - (36838723231/718502400)*n^5 + (4745796217531/15567552000)*n^4 - (170787179737/162162000)*n^3 + (51300697729/21621600)*n^2 - (74839579/180180)*n - 7017 for n>6 %e A223929 Some solutions for n=3 %e A223929 ..2..2..0..0....1..2..0..0....0..2..2..2....0..1..1..0....1..2..1..0 %e A223929 ..0..2..2..1....1..2..2..2....0..0..2..2....0..0..2..1....1..1..2..1 %e A223929 ..0..0..2..2....1..2..2..2....0..0..0..2....0..0..0..2....0..1..2..2 %K A223929 nonn %O A223929 1,1 %A A223929 _R. H. Hardin_ Mar 29 2013