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 A276251 #4 Aug 25 2016 11:06:25 %S A276251 41,576,1404,7316,43662,234431,1423062,8496628,48688320,288603590, %T A276251 1711519279,9976564722,58701625833,346524625690,2030788320548, %U A276251 11939927515262,70303418241786,412977048554900,2427488189698431 %N A276251 Number of 5Xn 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 A276251 Row 5 of A276248. %H A276251 R. H. Hardin, <a href="/A276251/b276251.txt">Table of n, a(n) for n = 1..210</a> %e A276251 Some solutions for n=4 %e A276251 ..0..1..2..2. .0..0..1..2. .0..1..1..0. .0..1..1..0. .0..0..1..1 %e A276251 ..2..0..1..1. .2..2..0..1. .2..0..1..2. .0..0..2..1. .2..0..0..1 %e A276251 ..2..2..0..0. .0..2..2..0. .1..2..0..0. .2..1..0..0. .1..1..2..0 %e A276251 ..1..1..2..0. .0..0..1..2. .1..1..2..2. .0..2..1..0. .2..0..1..2 %e A276251 ..2..0..1..2. .1..2..0..1. .2..0..0..2. .0..0..2..1. .2..2..0..0 %Y A276251 Cf. A276248. %K A276251 nonn %O A276251 1,1 %A A276251 _R. H. Hardin_, Aug 25 2016