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 A224259 #8 Mar 18 2025 22:33:00 %S A224259 86,1600,12032,59855,238366,816361,2485967,6868203,17467782,41364960, %T A224259 92057680,194025959,389786452,750442433,1391017095,2492190125, %U A224259 4330442992,7319061332,12062947260,19430764421,30648578146,47419866241,72077566743,107774701463,158721072338 %N A224259 Number of n X 5 0..2 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing. %H A224259 R. H. Hardin, <a href="/A224259/b224259.txt">Table of n, a(n) for n = 1..210</a> %F A224259 Empirical: a(n) = (1009/907200)*n^10 + (1489/181440)*n^9 + (6571/60480)*n^8 + (18937/30240)*n^7 + (148447/43200)*n^6 + (74281/8640)*n^5 + (10535767/181440)*n^4 + (1477907/45360)*n^3 + (1282339/25200)*n^2 - (151027/252)*n + 913 for n>4. %e A224259 Some solutions for n=3: %e A224259 ..0..0..1..1..0....0..1..1..1..1....0..0..0..0..2....1..0..0..0..0 %e A224259 ..0..0..1..1..1....1..2..1..1..1....0..0..0..1..2....1..1..0..0..0 %e A224259 ..0..1..2..1..1....2..2..2..2..1....0..0..1..2..2....2..1..0..0..0 %Y A224259 Column 5 of A224262. %K A224259 nonn %O A224259 1,1 %A A224259 _R. H. Hardin_, Apr 02 2013 %E A224259 Name corrected by _Andrew Howroyd_, Mar 18 2025