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 A298660 #4 Jan 24 2018 10:11:44 %S A298660 0,1,1,1,3,1,2,7,7,2,3,13,15,13,3,5,23,19,19,23,5,8,49,23,40,23,49,8, %T A298660 13,95,34,85,85,34,95,13,21,177,63,173,177,173,63,177,21,34,359,96, %U A298660 322,431,431,322,96,359,34,55,705,147,635,876,1116,876,635,147,705,55,89,1351 %N A298660 T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 2, 4, 6 or 7 king-move adjacent elements, with upper left element zero. %C A298660 Table starts %C A298660 ..0...1...1....2....3.....5.....8.....13......21......34.......55........89 %C A298660 ..1...3...7...13...23....49....95....177.....359.....705.....1351......2689 %C A298660 ..1...7..15...19...23....34....63.....96.....147.....233......368.......588 %C A298660 ..2..13..19...40...85...173...322....635....1325....2806.....5877.....12293 %C A298660 ..3..23..23...85..177...431...876...2137....5002...11687....27591.....64253 %C A298660 ..5..49..34..173..431..1116..2562...6711...17405...48462...125671....334571 %C A298660 ..8..95..63..322..876..2562..7964..24801...74358..242072...745571...2349275 %C A298660 .13.177..96..635.2137..6711.24801..89543..322065.1213296..4468276..16453935 %C A298660 .21.359.147.1325.5002.17405.74358.322065.1367704.6098314.26543249.116098205 %H A298660 R. H. Hardin, <a href="/A298660/b298660.txt">Table of n, a(n) for n = 1..241</a> %F A298660 Empirical for column k: %F A298660 k=1: a(n) = a(n-1) +a(n-2) %F A298660 k=2: a(n) = 3*a(n-1) -2*a(n-2) +4*a(n-3) -10*a(n-4) +4*a(n-5) for n>6 %F A298660 k=3: [order 18] for n>19 %F A298660 k=4: [order 72] for n>73 %e A298660 Some solutions for n=5 k=4 %e A298660 ..0..1..1..0. .0..1..1..0. .0..0..1..0. .0..0..1..1. .0..1..0..0 %e A298660 ..0..0..0..0. .1..0..0..0. .1..0..1..0. .1..0..1..0. .0..1..0..1 %e A298660 ..0..0..0..0. .1..0..0..0. .1..1..1..1. .1..0..0..0. .1..1..1..1 %e A298660 ..0..1..0..1. .1..0..1..0. .1..1..1..1. .1..0..0..0. .1..1..1..1 %e A298660 ..1..1..0..1. .0..0..1..1. .1..0..0..1. .0..1..1..0. .1..0..0..1 %Y A298660 Column 1 is A000045(n-1). %Y A298660 Column 2 is A297852. %Y A298660 Column 3 is A298050. %K A298660 nonn,tabl %O A298660 1,5 %A A298660 _R. H. Hardin_, Jan 24 2018