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 A298919 #4 Jan 29 2018 07:56:24 %S A298919 0,4,1,2,3,5,8,16,21,34,55,89,144,236,377,610,987,1597,2584,4184,6765, %T A298919 10946,17711,28657,46368,75028,121393,196418,317811,514229,832040, %U A298919 1346272,2178309,3524578,5702887,9227465,14930352,24157820,39088169 %N A298919 Number of nX3 0..1 arrays with every element equal to 1, 3, 5, 7 or 8 king-move adjacent elements, with upper left element zero. %C A298919 Column 3 of A298924. %H A298919 R. H. Hardin, <a href="/A298919/b298919.txt">Table of n, a(n) for n = 1..210</a> %F A298919 Empirical: a(n) = a(n-1) +a(n-2) +a(n-6) -a(n-7) -a(n-8) %e A298919 All solutions for n=5 %e A298919 ..0..0..0. .0..0..0. .0..0..0 %e A298919 ..0..0..0. .0..0..0. .0..0..0 %e A298919 ..0..0..0. .0..0..0. .1..1..1 %e A298919 ..1..1..1. .0..0..0. .1..1..1 %e A298919 ..1..1..1. .0..0..0. .1..1..1 %Y A298919 Cf. A298924. %K A298919 nonn %O A298919 1,2 %A A298919 _R. H. Hardin_, Jan 29 2018