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 A223863 #6 Jul 23 2025 04:36:08 %S A223863 1163,165212,6818350,144081276,2030417942,21476594002,181330154458, %T A223863 1271807435844,7630189031428,40055722078772,187351337881293, %U A223863 792277748611083,3065939800657297,10966696897925829,36566451416331144 %N A223863 Number of nX7 0..3 arrays with rows and antidiagonals unimodal and columns nondecreasing. %C A223863 Column 7 of A223864 %H A223863 R. H. Hardin, <a href="/A223863/b223863.txt">Table of n, a(n) for n = 1..210</a> %F A223863 Empirical: a(n) = (3642102403/12772735542927360000)*n^21 + (3642102403/304112751022080000)*n^20 + (5501403851/18246765061324800)*n^19 + (1301866883/246245142528000)*n^18 + (321344829121/4573124075520000)*n^17 + (9671690543/13076743680000)*n^16 + (48483224873/7604629401600)*n^15 + (4261834903427/94152554496000)*n^14 + (1535291055316393/5649153269760000)*n^13 + (98414490687917/72425041920000)*n^12 + (170390859823/29561241600)*n^11 + (33527325663863/1609445376000)*n^10 + (2567156664752496221/39544072888320000)*n^9 + (78187026472193263/470762772480000)*n^8 + (8882688677555591/28245766348800)*n^7 + (112344931028903/452656512000)*n^6 - (18857407511117083/95273418240000)*n^5 - (193916745450429061/55576160640000)*n^4 - (232978788696097/75811583232)*n^3 + (3865849954293617/293318625600)*n^2 + (834897119951/9699690)*n - 164695 for n>6 %e A223863 Some solutions for n=3 %e A223863 ..0..0..0..0..0..0..0....0..0..0..2..2..2..0....0..0..0..0..1..1..1 %e A223863 ..0..0..0..0..0..0..1....0..0..0..2..3..3..2....0..0..0..2..2..1..1 %e A223863 ..0..0..0..0..0..2..1....0..0..1..2..3..3..3....0..0..3..3..3..3..3 %K A223863 nonn %O A223863 1,1 %A A223863 _R. H. Hardin_ Mar 28 2013