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 A224377 #6 Jul 23 2025 05:08:02 %S A224377 243,11664,132236,800309,3607078,13831334,48166179,158023549, %T A224377 497580715,1514359253,4458436636,12678906115,34773215421,91905020703, %U A224377 234118674737,575345712656,1365918264285,3137981575530,6988511558308,15115188591949 %N A224377 Number of 5Xn 0..2 arrays with rows unimodal and antidiagonals nondecreasing. %C A224377 Row 5 of A224374 %H A224377 R. H. Hardin, <a href="/A224377/b224377.txt">Table of n, a(n) for n = 1..210</a> %F A224377 Empirical: a(n) = (1/1379196149760000)*n^20 + (1/12538146816000)*n^19 + (467/101624979456000)*n^18 + (223/1302884352000)*n^17 + (67777/14944849920000)*n^16 + (8993/99632332800)*n^15 + (29436877/20922789888000)*n^14 + (26572241/1494484992000)*n^13 + (439786693/2299207680000)*n^12 + (20411147/10948608000)*n^11 + (8076494051/459841536000)*n^10 + (1128125897/6967296000)*n^9 + (3054806701103/2179457280000)*n^8 + (547815604487/53374464000)*n^7 + (2418856630291/41513472000)*n^6 + (950711499611/4790016000)*n^5 + (286543564329947/1323241920000)*n^4 - (4310267256629/5513508000)*n^3 + (49217261945707/48886437600)*n^2 + (184937368403/116396280)*n - 3058 for n>3 %e A224377 Some solutions for n=3 %e A224377 ..1..2..0....0..0..0....1..1..1....2..0..0....1..0..0....0..0..1....1..0..0 %e A224377 ..2..0..0....1..2..0....1..2..0....1..0..0....1..1..1....0..1..0....0..1..0 %e A224377 ..0..0..0....2..0..0....2..0..0....1..0..0....2..2..2....2..1..0....2..1..0 %e A224377 ..0..0..0....1..1..1....2..2..1....2..1..0....2..2..2....1..1..1....2..1..0 %e A224377 ..2..2..1....2..1..0....2..2..0....1..2..2....2..2..1....2..2..2....2..2..1 %K A224377 nonn %O A224377 1,1 %A A224377 _R. H. Hardin_ Apr 05 2013