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 A275570 #4 Aug 01 2016 21:32:19 %S A275570 48,13824,27360,54150,248520,1140576,5360184,25190406,121255722, %T A275570 583672614,2856462882,13979378166,68872236498,339313015494, %U A275570 1674808590654,8266655528214,40869197474880,202051639449600,1000919771188800 %N A275570 Number of 7Xn 0..2 arrays with no element equal to any value at offset (-2,0) (-1,2) or (0,-2) and new values introduced in order 0..2. %C A275570 Row 7 of A275565. %H A275570 R. H. Hardin, <a href="/A275570/b275570.txt">Table of n, a(n) for n = 1..210</a> %e A275570 Some solutions for n=4 %e A275570 ..0..0..1..1. .0..1..2..0. .0..1..2..0. .0..1..1..2. .0..1..2..0 %e A275570 ..0..2..2..1. .1..2..2..1. .0..2..2..0. .0..0..1..1. .1..1..0..2 %e A275570 ..1..2..2..0. .1..0..0..2. .1..2..0..1. .2..2..0..0. .2..0..1..2 %e A275570 ..1..1..0..0. .2..1..1..0. .2..0..0..2. .1..2..2..0. .0..0..1..1 %e A275570 ..2..1..1..2. .0..2..2..1. .2..1..1..0. .1..1..2..2. .0..2..2..0 %e A275570 ..0..0..2..2. .0..0..2..2. .0..2..1..0. .0..0..1..1. .1..1..2..2 %e A275570 ..0..0..2..1. .1..1..0..0. .0..2..2..1. .2..2..1..1. .1..0..0..2 %Y A275570 Cf. A275565. %K A275570 nonn %O A275570 1,1 %A A275570 _R. H. Hardin_, Aug 01 2016