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 A276242 #6 Apr 21 2020 12:47:35 %S A276242 1,9,85,1447,43662,2069454,219977330,41132001645,12485740560874, %T A276242 8479969482488403,9954378022508358771 %N A276242 Number of n X n 0..2 arrays with no element equal to any value at offset (-2,-1), (-1,1) or (0,-2) and new values introduced in order 0..2. %C A276242 Diagonal of A276248. %e A276242 Some solutions for n=4 %e A276242 ..0..1..2..0. .0..1..1..2. .0..1..1..0. .0..1..1..0. .0..0..1..1 %e A276242 ..2..1..1..0. .2..0..1..1. .2..0..1..2. .2..0..1..1. .2..2..0..0 %e A276242 ..0..2..2..1. .1..2..2..0. .1..2..0..0. .1..2..2..0. .1..1..2..0 %e A276242 ..0..0..2..2. .0..0..2..2. .0..1..1..2. .1..1..2..0. .2..1..1..2 %Y A276242 Cf. A276248. %K A276242 nonn %O A276242 1,2 %A A276242 _R. H. Hardin_, Aug 25 2016