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 A224413 #6 Jul 23 2025 05:09:54 %S A224413 64,972,4636,13440,31710,68282,139638,275766,530583,999049,1844709, %T A224413 3342831,5946316,10384152,17805490,29986574,49622914,80735424, %U A224413 129226948,203634878,316136662,483878162,730710330,1089437826,1604704333 %N A224413 Number of 6Xn 0..1 arrays with rows unimodal and antidiagonals nondecreasing. %C A224413 Row 6 of A224409 %H A224413 R. H. Hardin, <a href="/A224413/b224413.txt">Table of n, a(n) for n = 1..210</a> %F A224413 Empirical: a(n) = (1/479001600)*n^12 + (1/7257600)*n^11 + (199/43545600)*n^10 + (1/10752)*n^9 + (19951/14515200)*n^8 + (5143/345600)*n^7 + (6148357/43545600)*n^6 + (3015961/1451520)*n^5 + (128983289/10886400)*n^4 + (40193333/604800)*n^3 + (444089893/1663200)*n^2 - (4351/20)*n - 222 for n>4 %e A224413 Some solutions for n=3 %e A224413 ..1..1..0....0..1..1....1..1..1....1..0..0....1..1..0....1..1..0....0..0..0 %e A224413 ..1..0..0....1..1..1....1..1..0....1..0..0....1..0..0....1..0..0....1..0..0 %e A224413 ..0..1..0....1..1..1....1..1..1....0..0..0....0..0..0....1..0..0....0..1..1 %e A224413 ..1..0..0....1..1..0....1..1..1....0..0..0....1..0..0....1..0..0....1..1..0 %e A224413 ..0..0..1....1..0..0....1..1..0....1..1..0....1..1..1....1..1..0....1..0..0 %e A224413 ..1..1..0....0..0..0....1..1..0....1..1..1....1..1..1....1..0..0....0..0..0 %K A224413 nonn %O A224413 1,1 %A A224413 _R. H. Hardin_ Apr 05 2013