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 A223618 #6 Jul 23 2025 04:17:44 %S A223618 22,484,6504,57238,367216,1856100,7795951,28248007,90732638,263650284, %T A223618 703980614,1748547620,4079672416,9012596316,18975151965,38281575869, %U A223618 74344179766,139521245076,253869738212,449160402594,774624001120 %N A223618 Number of nX6 0..1 arrays with rows and columns unimodal. %C A223618 Column 6 of A223620 %H A223618 R. H. Hardin, <a href="/A223618/b223618.txt">Table of n, a(n) for n = 1..210</a> %F A223618 Empirical: a(n) = (271/5443200)*n^12 + (2327/3326400)*n^11 + (39107/5443200)*n^10 + (1579/36288)*n^9 + (52553/259200)*n^8 + (192371/302400)*n^7 + (8636441/5443200)*n^6 + (56113/20160)*n^5 + (2901677/680400)*n^4 + (523927/113400)*n^3 + (23969/5400)*n^2 + (33487/13860)*n + 1 %e A223618 Some solutions for n=4 %e A223618 ..1..1..0..0..0..0....0..0..1..0..0..0....0..0..1..1..1..1....1..1..1..1..1..1 %e A223618 ..0..1..0..0..0..0....0..0..0..1..0..0....0..0..1..1..1..1....1..1..1..1..1..1 %e A223618 ..0..0..1..0..0..0....0..0..0..1..1..0....0..0..0..1..1..1....0..0..0..1..1..1 %e A223618 ..0..0..1..1..0..0....1..1..0..0..0..0....0..0..0..0..1..1....0..0..0..1..1..1 %K A223618 nonn %O A223618 1,1 %A A223618 _R. H. Hardin_ Mar 24 2013