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 A318343 #4 Aug 24 2018 11:04:59 %S A318343 1,2,2,4,6,4,8,10,10,8,16,20,20,20,16,32,42,36,36,42,32,64,89,76,67, %T A318343 76,89,64,128,190,160,148,148,160,190,128,256,407,344,343,393,343,344, %U A318343 407,256,512,873,748,817,1115,1115,817,748,873,512,1024,1874,1624,1975,3321 %N A318343 T(n,k)=Number of nXk 0..1 arrays with every element unequal to 0, 1, 2 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. %C A318343 Table starts %C A318343 ...1...2....4....8....16.....32......64......128.......256........512 %C A318343 ...2...6...10...20....42.....89.....190......407.......873.......1874 %C A318343 ...4..10...20...36....76....160.....344......748......1624.......3544 %C A318343 ...8..20...36...67...148....343.....817.....1975......4788......11644 %C A318343 ..16..42...76..148...393...1115....3321....10111.....30943......95244 %C A318343 ..32..89..160..343..1115...4133...16267....66070....270320....1112195 %C A318343 ..64.190..344..817..3321..16267...86487...476348...2647555...14797928 %C A318343 .128.407..748.1975.10111..66070..476348..3590263..27322989..209259065 %C A318343 .256.873.1624.4788.30943.270320.2647555.27322989.285034170.2994059337 %H A318343 R. H. Hardin, <a href="/A318343/b318343.txt">Table of n, a(n) for n = 1..611</a> %F A318343 Empirical for column k: %F A318343 k=1: a(n) = 2*a(n-1) %F A318343 k=2: a(n) = 2*a(n-1) +a(n-2) -a(n-3) -a(n-4) for n>6 %F A318343 k=3: a(n) = 2*a(n-1) +2*a(n-2) -3*a(n-3) -2*a(n-4) +2*a(n-5) for n>6 %F A318343 k=4: [order 8] for n>9 %F A318343 k=5: [order 15] for n>18 %F A318343 k=6: [order 23] for n>27 %F A318343 k=7: [order 36] for n>41 %e A318343 Some solutions for n=5 k=4 %e A318343 ..0..1..1..0. .0..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..0 %e A318343 ..1..1..0..0. .1..1..1..1. .0..1..0..0. .0..0..0..0. .1..1..1..1 %e A318343 ..1..0..0..1. .1..1..1..0. .0..0..1..0. .1..1..1..1. .1..1..1..1 %e A318343 ..0..0..1..1. .1..1..0..0. .0..0..0..0. .1..1..1..0. .1..1..1..0 %e A318343 ..0..1..1..0. .1..0..0..1. .0..0..0..1. .1..1..0..0. .1..1..0..0 %Y A318343 Column 1 is A000079(n-1). %Y A318343 Column 2 is A317759. %K A318343 nonn,tabl %O A318343 1,2 %A A318343 _R. H. Hardin_, Aug 24 2018