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 A233155 #6 Sep 03 2022 20:38:27 %S A233155 3,6,9,12,24,27,24,72,96,81,48,216,432,384,243,96,648,1944,2592,1536, %T A233155 729,192,1944,8856,17496,15552,6144,2187,384,5832,40392,121176,157464, %U A233155 93312,24576,6561,768,17496,184248,842616,1658232,1417176,559872,98304,19683 %N A233155 T(n,k) = Number of n X k 0..2 arrays with no element x(i,j) adjacent to value 2-x(i,j) horizontally or antidiagonally. %C A233155 Table starts %C A233155 .....3.......6........12.........24...........48.............96 %C A233155 .....9......24........72........216..........648...........1944 %C A233155 ....27......96.......432.......1944.........8856..........40392 %C A233155 ....81.....384......2592......17496.......121176.........842616 %C A233155 ...243....1536.....15552.....157464......1658232.......17587584 %C A233155 ...729....6144.....93312....1417176.....22692312......367125912 %C A233155 ..2187...24576....559872...12754584....310536504.....7663517136 %C A233155 ..6561...98304...3359232..114791256...4249585944...159971190624 %C A233155 .19683..393216..20155392.1033121304..58154132088..3339300422232 %C A233155 .59049.1572864.120932352.9298091736.795819434328.69705848287656 %H A233155 R. H. Hardin, <a href="/A233155/b233155.txt">Table of n, a(n) for n = 1..390</a> %F A233155 Empirical for column k: %F A233155 k=1: a(n) = 3*a(n-1). %F A233155 k=2: a(n) = 4*a(n-1). %F A233155 k=3: a(n) = 6*a(n-1). %F A233155 k=4: a(n) = 9*a(n-1). %F A233155 k=5: a(n) = 15*a(n-1) -18*a(n-2). %F A233155 k=6: a(n) = 25*a(n-1) -90*a(n-2) +81*a(n-3). %F A233155 k=7: a(n) = 42*a(n-1) -351*a(n-2) +972*a(n-3) -810*a(n-4). %F A233155 Empirical for row n: %F A233155 n=1: a(n) = 2*a(n-1). %F A233155 n=2: a(n) = 3*a(n-1) for n>2. %F A233155 n=3: a(n) = 5*a(n-1) -2*a(n-2) for n>4. %F A233155 n=4: a(n) = 9*a(n-1) -15*a(n-2) +6*a(n-3) for n>7. %F A233155 n=5: [order 7] for n>11. %F A233155 n=6: [order 9] for n>15. %F A233155 n=7: [order 27] for n>33. %e A233155 Some solutions for n=4, k=4 %e A233155 ..1..2..2..1....1..2..2..1....0..0..0..0....1..2..1..0....2..1..0..1 %e A233155 ..2..1..2..2....2..1..0..1....1..0..1..2....1..0..0..0....0..1..0..1 %e A233155 ..2..1..2..1....2..1..0..1....1..0..1..0....0..0..1..0....2..1..2..1 %e A233155 ..0..1..2..2....0..1..0..0....1..0..0..1....0..0..0..0....2..1..0..0 %Y A233155 Column 1 is A000244. %Y A233155 Column 2 is A002023(n-1). %Y A233155 Column 3 is 2*A000400. %Y A233155 Column 4 is 3*A055275. %Y A233155 Row 1 is A003945. %Y A233155 Row 2 is A005051(n-1) for n>1. %K A233155 nonn,tabl %O A233155 1,1 %A A233155 _R. H. Hardin_, Dec 05 2013