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 A196287 #7 Jun 02 2025 04:20:07 %S A196287 1,3,3,4,5,4,5,8,8,5,8,17,7,17,8,12,34,50,50,34,12,17,62,111,335,111, %T A196287 62,17,25,123,259,882,882,259,123,25,37,243,728,2998,3621,2998,728, %U A196287 243,37,54,471,1800,13533,22971,22971,13533,1800,471,54,79,924,4696,57281 %N A196287 T(n,k)=Number of nXk 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 2,0,3,1,4 for x=0,1,2,3,4. %C A196287 Every 0 is next to 0 2's, every 1 is next to 1 0's, every 2 is next to 2 3's, every 3 is next to 3 1's, every 4 is next to 4 4's %C A196287 Table starts %C A196287 ..1...3.....4......5........8........12..........17...........25.............37 %C A196287 ..3...5.....8.....17.......34........62.........123..........243............471 %C A196287 ..4...8.....7.....50......111.......259.........728.........1800...........4696 %C A196287 ..5..17....50....335......882......2998.......13533........57281.........234589 %C A196287 ..8..34...111....882.....3621.....22971......138924.......684002........3547662 %C A196287 .12..62...259...2998....22971....193137.....1306488.....10441374.......87352550 %C A196287 .17.123...728..13533...138924...1306488....13307143....182868341.....2172296568 %C A196287 .25.243..1800..57281...684002..10441374...182868341...3369153109....48734434499 %C A196287 .37.471..4696.234589..3547662..87352550..2172296568..48734434499..1022753961763 %C A196287 .54.924.12185.894628.21119073.710287441.23151489546.745373469270.25671148871894 %H A196287 R. H. Hardin, <a href="/A196287/b196287.txt">Table of n, a(n) for n = 1..219</a> %e A196287 Some solutions for n=6 k=4 %e A196287 ..1..3..1..0....1..1..0..1....0..0..1..1....0..0..1..1....0..1..3..1 %e A196287 ..0..1..1..0....0..3..1..1....1..3..1..0....1..1..1..0....0..3..1..0 %e A196287 ..1..1..3..1....0..1..1..0....3..1..3..1....3..1..1..1....0..1..1..0 %e A196287 ..1..0..0..1....0..3..1..0....1..0..0..1....1..0..0..1....0..3..1..0 %e A196287 ..1..1..1..1....1..1..1..0....1..1..3..1....1..1..3..1....0..1..1..0 %e A196287 ..0..1..1..0....1..0..1..1....0..1..1..0....0..1..1..0....0..1..1..0 %Y A196287 Column 1 is A179070(n+2) %Y A196287 Column 2 is A196140 %K A196287 nonn,tabl %O A196287 1,2 %A A196287 _R. H. Hardin_ Sep 30 2011