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 A281710 #7 Feb 20 2019 05:35:07 %S A281710 1,7,8,14,17,22,30,43,64,98,153,242,386,619,996,1606,2593,4190,6774, %T A281710 10955,17720,28666,46377,75034,121402,196427,317820,514238,832049, %U A281710 1346278,2178318,3524587,5702896,9227474,14930361,24157826,39088178 %N A281710 Number of n X 3 0..1 arrays with no element unequal to a strict majority of its horizontal, diagonal and antidiagonal neighbors and with new values introduced in order 0 sequentially upwards. %H A281710 R. H. Hardin, <a href="/A281710/b281710.txt">Table of n, a(n) for n = 1..210</a> %F A281710 Empirical: a(n) = 2*a(n-1) - a(n-3) for n>6. %F A281710 Empirical g.f.: x*(1 + 5*x - 6*x^2 - x^3 - 4*x^4 - 4*x^5) / ((1 - x)*(1 - x - x^2)). - _Colin Barker_, Feb 20 2019 %e A281710 Some solutions for n=4: %e A281710 ..0..0..0. .0..0..0. .0..0..1. .0..0..1. .0..1..1. .0..0..1. .0..1..0 %e A281710 ..1..1..1. .0..0..0. .0..1..0. .0..1..0. .1..0..1. .0..1..0. .1..0..1 %e A281710 ..1..1..1. .0..0..0. .1..0..1. .1..0..1. .0..1..0. .1..0..1. .0..1..0 %e A281710 ..1..1..1. .1..1..1. .0..1..1. .0..1..0. .0..0..1. .1..1..0. .1..0..1 %Y A281710 Column 3 of A281715. %K A281710 nonn %O A281710 1,2 %A A281710 _R. H. Hardin_, Jan 28 2017