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 A269056 #4 Feb 18 2016 11:41:52 %S A269056 243,2430,17346,183072,1643376,15547380,140497512,1273499256, %T A269056 11354964888,100764874440,886829123676,7765850889120,67643548943508, %U A269056 586749197487720,5069733374448192,43657996370224608,374818434125094900 %N A269056 Number of 5Xn 0..2 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two not more than once. %C A269056 Row 5 of A269052. %H A269056 R. H. Hardin, <a href="/A269056/b269056.txt">Table of n, a(n) for n = 1..210</a> %F A269056 Empirical: a(n) = 12*a(n-1) +26*a(n-2) -566*a(n-3) -123*a(n-4) +8804*a(n-5) -4121*a(n-6) -59620*a(n-7) +55115*a(n-8) +183692*a(n-9) -256127*a(n-10) -211910*a(n-11) +498819*a(n-12) -48036*a(n-13) -371692*a(n-14) +214008*a(n-15) +43848*a(n-16) -64656*a(n-17) +8640*a(n-18) +5184*a(n-19) -1296*a(n-20) for n>22 %e A269056 Some solutions for n=4 %e A269056 ..0..1..2..1. .1..0..1..0. .0..1..2..1. .0..0..1..0. .1..1..0..0 %e A269056 ..2..1..2..1. .0..0..1..2. .0..1..0..1. .1..2..1..2. .0..0..0..0 %e A269056 ..2..1..0..2. .1..0..1..2. .0..1..2..1. .2..2..2..2. .0..0..0..1 %e A269056 ..0..1..2..1. .0..0..1..0. .0..1..0..0. .2..1..2..1. .0..0..0..1 %e A269056 ..0..1..2..2. .0..0..1..0. .0..0..0..0. .0..1..2..2. .1..0..0..1 %Y A269056 Cf. A269052. %K A269056 nonn %O A269056 1,1 %A A269056 _R. H. Hardin_, Feb 18 2016