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 A230184 #6 Jun 02 2025 08:42:30 %S A230184 0,3,0,3,9,0,9,27,33,0,15,159,231,129,0,33,825,3411,1971,513,0,63, %T A230184 4395,44487,73857,16815,2049,0,129,23307,596973,2432241,1603431, %U A230184 143451,8193,0,255,123729,7957785,82359177,133265847,34825803,1223799,32769,0,513 %N A230184 T(n,k)=Number of nXk 0..2 arrays x(i,j) with each element horizontally or antidiagonally next to at least one element with value 2-x(i,j). %C A230184 Table starts %C A230184 .0.....3........3...........9.............15................33 %C A230184 .0.....9.......27.........159............825..............4395 %C A230184 .0....33......231........3411..........44487............596973 %C A230184 .0...129.....1971.......73857........2432241..........82359177 %C A230184 .0...513....16815.....1603431......133265847.......11393567289 %C A230184 .0..2049...143451....34825803.....7303192425.....1576417829097 %C A230184 .0..8193..1223799...756450105...400233701367...218117038953009 %C A230184 .0.32769.10440387.16430979183.21933865129257.30179260908320577 %H A230184 R. H. Hardin, <a href="/A230184/b230184.txt">Table of n, a(n) for n = 1..238</a> %F A230184 Empirical for column k: %F A230184 k=1: a(n) = a(n-1) %F A230184 k=2: a(n) = 5*a(n-1) -4*a(n-2) %F A230184 k=3: a(n) = 9*a(n-1) -4*a(n-2) %F A230184 k=4: a(n) = 26*a(n-1) -97*a(n-2) +89*a(n-3) -18*a(n-4) +a(n-5) %F A230184 k=5: [order 6] for n>8 %F A230184 k=6: [order 23] for n>24 %F A230184 k=7: [order 34] for n>37 %F A230184 Empirical for row n: %F A230184 n=1: a(n) = a(n-1) +2*a(n-2) %F A230184 n=2: a(n) = 4*a(n-1) +7*a(n-2) +a(n-3) -6*a(n-4) -5*a(n-5) for n>6 %F A230184 n=3: [order 21] for n>23 %F A230184 n=4: [order 93] for n>96 %e A230184 Some solutions for n=3 k=4 %e A230184 ..2..0..1..1....0..2..1..1....2..0..0..1....0..2..2..0....1..1..2..2 %e A230184 ..0..2..2..0....0..0..2..2....0..2..1..1....0..1..2..0....2..0..0..0 %e A230184 ..0..2..1..1....1..1..0..2....1..1..0..2....1..2..0..2....0..2..2..0 %Y A230184 Column 2 is A084508(n+1) %Y A230184 Row 1 is A062510(n-1) %K A230184 nonn,tabl %O A230184 1,2 %A A230184 _R. H. Hardin_, Oct 11 2013