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 A223635 #6 Jul 23 2025 04:19:07 %S A223635 22,484,5699,42109,230619,1026377,3907140,13135511,39889555,111242770, %T A223635 288488044,702553878,1619299148,3555008655,7473337157,15110365462, %U A223635 29495673113,55765989646,102405932407,183099750019,319441371676 %N A223635 Number of nX6 0..1 arrays with rows, antidiagonals and columns unimodal. %C A223635 Column 6 of A223637 %H A223635 R. H. Hardin, <a href="/A223635/b223635.txt">Table of n, a(n) for n = 1..210</a> %F A223635 Empirical: a(n) = (271/5443200)*n^12 - (10327/9979200)*n^11 + (61997/2177280)*n^10 - (21923/80640)*n^9 + (417761/1814400)*n^8 + (37222841/604800)*n^7 - (2521405483/2177280)*n^6 + (8668581613/725760)*n^5 - (414044081579/5443200)*n^4 + (88564150211/302400)*n^3 - (17419930607/30240)*n^2 + (542846047/3080)*n + 850576 for n>8 %e A223635 Some solutions for n=4 %e A223635 ..0..1..1..1..0..0....1..1..1..0..0..0....1..1..1..0..0..0....0..0..0..0..1..1 %e A223635 ..0..1..1..1..1..0....1..1..1..0..0..0....0..0..1..1..1..1....0..1..1..1..1..0 %e A223635 ..0..1..1..1..0..0....0..1..1..1..0..0....0..0..1..1..1..1....0..1..1..1..1..0 %e A223635 ..1..1..1..1..0..0....0..0..1..1..0..0....0..0..0..0..0..1....0..0..1..1..0..0 %K A223635 nonn %O A223635 1,1 %A A223635 _R. H. Hardin_ Mar 24 2013