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 A196455 #7 Apr 17 2022 20:19:02 %S A196455 17,320,3966,76809,2032584,46887621,926499600,17962317556, %T A196455 351103877665,6945098996988,139065692664815,2795329197283554, %U A196455 56072977068447935,1121420878698363003,22398808824228997399,447457890891091698310 %N A196455 Number of n X 7 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 3,0,2,4,1 for x=0,1,2,3,4. %C A196455 Every 0 is next to 0 3's, every 1 is next to 1 0's, every 2 is next to 2 2's, every 3 is next to 3 4's, every 4 is next to 4 1's. %C A196455 Column 7 of A196456. %H A196455 R. H. Hardin, <a href="/A196455/b196455.txt">Table of n, a(n) for n = 1..95</a> %e A196455 Some solutions for n=4 %e A196455 ..2..2..2..1..1..1..0....0..1..1..0..0..1..1....0..1..1..0..0..0..0 %e A196455 ..2..0..2..0..0..2..2....0..2..2..2..2..2..0....2..2..1..0..0..0..0 %e A196455 ..2..2..2..1..1..2..2....0..2..0..0..1..2..0....2..2..1..0..0..2..2 %e A196455 ..0..0..0..1..1..0..0....1..2..2..2..2..2..1....0..0..1..1..1..2..2 %Y A196455 Cf. A196456. %K A196455 nonn %O A196455 1,1 %A A196455 _R. H. Hardin_, Oct 02 2011