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 A184123 #8 Oct 20 2022 23:06:40 %S A184123 20,561,14178,276427,4249486,53817407,581588614,5503143135, %T A184123 46473256070,355407459056,2489794107266,16126296889260,97309331427298, %U A184123 550557601317077,2936599872342895,14836021866212493,71284139688101545 %N A184123 Number of n X 3 0..3 arrays with rows and columns in nondecreasing order. %C A184123 Column 3 of A184129. %H A184123 Ron Hardin, <a href="/A184123/b184123.txt">Table of n, a(n) for n = 1..200</a> %F A184123 Empirical: a(n)=64*a(n-1)-2016*a(n-2)+41664*a(n-3)-635376*a(n-4)+7624512*a(n-5)-74974368*a(n-6)+621216192*a(n-7)-4426165368*a(n-8)+27540584512*a(n-9)-151473214816*a(n-10)+743595781824*a(n-11)-3284214703056*a(n-12)+13136858812224*a(n-13)-47855699958816*a(n-14)+159518999862720*a(n-15)-488526937079580*a(n-16)+1379370175283520*a(n-17)-3601688791018080*a(n-18)+8719878125622720*a(n-19)-19619725782651120*a(n-20)+41107996877935680*a(n-21)-80347448443237920*a(n-22)+146721427591999680*a(n-23)-250649105469666120*a(n-24)+401038568751465792*a(n-25)-601557853127198688*a(n-26)+846636978475316672*a(n-27)-1118770292985239888*a(n-28)+1388818294740297792*a(n-29)-1620288010530347424*a(n-30)+1777090076065542336*a(n-31)-1832624140942590534*a(n-32)+1777090076065542336*a(n-33)-1620288010530347424*a(n-34)+1388818294740297792*a(n-35)-1118770292985239888*a(n-36)+846636978475316672*a(n-37)-601557853127198688*a(n-38)+401038568751465792*a(n-39)-250649105469666120*a(n-40)+146721427591999680*a(n-41)-80347448443237920*a(n-42)+41107996877935680*a(n-43)-19619725782651120*a(n-44)+8719878125622720*a(n-45)-3601688791018080*a(n-46)+1379370175283520*a(n-47)-488526937079580*a(n-48)+159518999862720*a(n-49)-47855699958816*a(n-50)+13136858812224*a(n-51)-3284214703056*a(n-52)+743595781824*a(n-53)-151473214816*a(n-54)+27540584512*a(n-55)-4426165368*a(n-56)+621216192*a(n-57)-74974368*a(n-58)+7624512*a(n-59)-635376*a(n-60)+41664*a(n-61)-2016*a(n-62)+64*a(n-63)-a(n-64) (=polynomial of degree 63). %e A184123 Some solutions for 5 X 3 %e A184123 ..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0 %e A184123 ..0..0..0....0..0..2....0..1..2....0..1..2....0..0..1....0..1..2....0..1..2 %e A184123 ..0..1..2....1..1..3....1..1..1....0..2..0....0..1..2....0..1..2....1..1..0 %e A184123 ..2..2..3....1..3..0....3..1..2....1..0..1....2..0..0....1..2..1....1..3..1 %e A184123 ..3..2..1....2..0..2....3..2..3....1..1..0....2..1..3....3..0..0....2..3..3 %Y A184123 Cf. A184129. %K A184123 nonn %O A184123 1,1 %A A184123 _R. H. Hardin_, Jan 09 2011