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 A293100 #6 Apr 05 2020 20:10:14 %S A293100 0,0,0,0,0,0,0,9,5,0,0,42,48,30,0,1,150,567,554,126,0,3,596,3619,8088, %T A293100 3334,520,0,10,2220,29952,114318,115870,30837,2088,0,24,8376,205195, %U A293100 1676740,3125547,1710994,202363,8192,0,60,31959,1668655,24773296 %N A293100 T(n,k) = Number of n X k 0..1 arrays with the number of 1's horizontally, diagonally or antidiagonally adjacent to some 0 two less than the number of 0's adjacent to some 1. %C A293100 Table starts %C A293100 .0.....0........0..........0.............0................1..................3 %C A293100 .0.....0........9.........42...........150..............596...............2220 %C A293100 .0.....5.......48........567..........3619............29952.............205195 %C A293100 .0....30......554.......8088........114318..........1676740...........24773296 %C A293100 .0...126.....3334.....115870.......3125547.........95603353.........2728695681 %C A293100 .0...520....30837....1710994......96199260.......5589631828.......328979478088 %C A293100 .0..2088...202363...25504769....2804027631.....331401441383.....38469698642410 %C A293100 .0..8192..1733660..383909610...85892871786...19865025530414...4665971856266714 %C A293100 .0.32083.12139768.5821195059.2579471093496.1200437139032383.560706154294046909 %H A293100 R. H. Hardin, <a href="/A293100/b293100.txt">Table of n, a(n) for n = 1..143</a> %e A293100 Some solutions for n=4, k=4 %e A293100 ..0..0..0..0. .0..0..0..1. .0..1..1..0. .1..1..0..1. .1..1..0..0 %e A293100 ..1..0..0..0. .1..1..0..0. .1..0..0..1. .0..1..0..1. .0..1..1..0 %e A293100 ..1..1..0..1. .1..0..1..0. .1..0..1..0. .0..0..1..0. .1..1..0..0 %e A293100 ..0..0..1..0. .0..1..0..1. .0..1..0..0. .0..0..0..1. .1..0..0..0 %Y A293100 Column 2 is A286973. %Y A293100 Row 1 is A286209. %K A293100 nonn,tabl %O A293100 1,8 %A A293100 _R. H. Hardin_, Sep 30 2017