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 A223826 #6 Jul 23 2025 04:34:32 %S A223826 22,484,6166,51136,310396,1492552,5995781,20879061,64727664,182215264, %T A223826 472897132,1144905802,2610251996,5646952970,11664925145,23128319257, %U A223826 44207709722,81762385076,146787187114,256501341004,437310109972 %N A223826 Number of nX3 0..2 arrays with rows and columns unimodal. %C A223826 Column 3 of A223831 %H A223826 R. H. Hardin, <a href="/A223826/b223826.txt">Table of n, a(n) for n = 1..210</a> %F A223826 Empirical: a(n) = (5051/239500800)*n^12 + (17911/39916800)*n^11 + (113633/21772800)*n^10 + (27157/725760)*n^9 + (1331621/7257600)*n^8 + (36461/57600)*n^7 + (35192219/21772800)*n^6 + (2190431/725760)*n^5 + (24210049/5443200)*n^4 + (4187689/907200)*n^3 + (882989/207900)*n^2 + (2173/990)*n + 1 %e A223826 Some solutions for n=3 %e A223826 ..0..0..2....1..2..0....1..0..0....2..0..0....1..1..1....1..1..1....1..2..0 %e A223826 ..1..2..0....2..2..1....2..2..1....1..1..0....0..1..0....1..1..0....1..1..1 %e A223826 ..1..1..0....0..0..0....2..2..0....1..1..2....0..2..0....1..0..0....2..1..0 %K A223826 nonn %O A223826 1,1 %A A223826 _R. H. Hardin_ Mar 27 2013