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 A223917 #6 Jul 23 2025 04:38:52 %S A223917 239,9503,140236,1226491,7906972,41334135,183720802,715114500, %T A223917 2489822632,7881608430,22979660094,62362461624,158897321204, %U A223917 382876827441,877788083326,1924637063386,4053719944340,8232970841532,16176720454482 %N A223917 Number of nX7 0..2 arrays with rows and antidiagonals unimodal and columns nondecreasing. %C A223917 Column 7 of A223918 %H A223917 R. H. Hardin, <a href="/A223917/b223917.txt">Table of n, a(n) for n = 1..210</a> %F A223917 Empirical: a(n) = (118519/21794572800)*n^14 + (118519/1037836800)*n^13 + (59179/34214400)*n^12 + (1397923/79833600)*n^11 + (117161/870912)*n^10 + (825457/1036800)*n^9 + (584642563/152409600)*n^8 + (98173459/7257600)*n^7 + (34767841/777600)*n^6 + (161988637/1814400)*n^5 + (3918685081/29937600)*n^4 - (1351991/44550)*n^3 - (53319445009/75675600)*n^2 - (347075779/180180)*n + 4742 for n>4 %e A223917 Some solutions for n=3 %e A223917 ..0..0..1..1..2..1..0....0..0..0..1..1..2..1....0..0..0..0..0..1..0 %e A223917 ..0..0..1..1..2..1..1....0..0..1..1..2..2..1....0..0..2..1..1..1..1 %e A223917 ..0..0..1..1..2..2..1....0..1..2..2..2..2..1....0..1..2..2..2..1..1 %K A223917 nonn %O A223917 1,1 %A A223917 _R. H. Hardin_ Mar 29 2013