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 A224356 #6 Jul 23 2025 05:07:04 %S A224356 243,7776,45064,160362,495985,1421762,3816783,9630357,22913143, %T A224356 51614480,110565824,226229854,443991585,839005884,1531899199, %U A224356 2710956117,4662807601,7814081454,12786980756,20472326754,32124242991,49481371374 %N A224356 Number of 5Xn 0..2 arrays with diagonals and antidiagonals unimodal and rows nondecreasing. %C A224356 Row 5 of A224353 %H A224356 R. H. Hardin, <a href="/A224356/b224356.txt">Table of n, a(n) for n = 1..210</a> %F A224356 Empirical: a(n) = (1009/907200)*n^10 + (1489/181440)*n^9 + (7699/60480)*n^8 + (26497/30240)*n^7 + (234967/43200)*n^6 + (430969/8640)*n^5 - (23036177/181440)*n^4 + (81980567/45360)*n^3 - (18258277/8400)*n^2 + (3586529/630)*n - 10675 for n>5 %e A224356 Some solutions for n=3 %e A224356 ..1..1..1....0..2..2....0..0..0....0..0..2....1..1..1....0..0..1....0..0..2 %e A224356 ..1..2..2....0..1..2....0..2..2....0..1..1....1..1..2....1..1..2....0..2..2 %e A224356 ..0..1..1....1..1..2....0..1..2....0..0..0....1..1..2....0..1..1....1..2..2 %e A224356 ..1..2..2....1..1..1....0..1..1....0..0..2....0..2..2....0..2..2....2..2..2 %e A224356 ..0..1..2....0..0..2....0..0..0....0..0..0....1..1..2....1..1..2....0..0..1 %K A224356 nonn %O A224356 1,1 %A A224356 _R. H. Hardin_ Apr 04 2013