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 A223986 #6 Jul 23 2025 04:46:08 %S A223986 1163,165212,8350154,219861244,3661410444,43307637038,392525216516, %T A223986 2873859236297,17659521902693,93729371629362,439299889862080, %U A223986 1850116568165210,7099972695985506,25111747601307148,82630828730010090 %N A223986 Number of nX7 0..3 arrays with rows unimodal and columns nondecreasing. %C A223986 Column 7 of A223987 %H A223986 R. H. Hardin, <a href="/A223986/b223986.txt">Table of n, a(n) for n = 1..210</a> %F A223986 Empirical: a(n) = (3642102403/12772735542927360000)*n^21 + (1828819507/93573154160640000)*n^20 + (115124770751/182467650613248000)*n^19 + (8318749/652138905600)*n^18 + (446143076989/2462451425280000)*n^17 + (1206525314927/627683696640000)*n^16 + (31263943588093/1977203644416000)*n^15 + (7783056899227/75322043596800)*n^14 + (3079623865184773/5649153269760000)*n^13 + (32370958783969/13795246080000)*n^12 + (120111458340271/14485008384000)*n^11 + (93158829341993/3862668902400)*n^10 + (2280948080961292511/39544072888320000)*n^9 + (371762262630263/3292047360000)*n^8 + (5068740614675741/28245766348800)*n^7 + (34137353132761/149448499200)*n^6 + (11720474642505173/51301071360000)*n^5 + (539294046816389/3087564480000)*n^4 + (12076668593664427/123193822752000)*n^3 + (2595939553/68468400)*n^2 + (104988181/11639628)*n + 1 %e A223986 Some solutions for n=3 %e A223986 ..0..0..0..0..1..0..0....0..0..0..0..1..1..0....0..0..0..0..0..1..1 %e A223986 ..0..0..0..1..1..1..0....0..0..0..2..2..3..0....0..0..0..2..3..2..2 %e A223986 ..0..0..2..3..1..1..1....0..0..2..2..3..3..2....0..0..0..2..3..3..3 %K A223986 nonn %O A223986 1,1 %A A223986 _R. H. Hardin_ Mar 30 2013