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 A299446 #6 Apr 11 2022 12:11:00 %S A299446 3,4,1,4,10,6,11,41,24,42,169,100,159,710,405,643,2995,1673,2659, %T A299446 12648,6948,11132,53434,29109,46870,225916,122510,197807,955669, %U A299446 517066,835904,4044687,2185734,3535227,17123968,9247255,14959235,72513441,39141547 %N A299446 Number of n X 3 0..1 arrays with every element equal to 0, 1, 3, 5, 6 or 8 king-move adjacent elements, with upper left element zero. %C A299446 Column 3 of A299451. %H A299446 R. H. Hardin, <a href="/A299446/b299446.txt">Table of n, a(n) for n = 1..210</a> %F A299446 Empirical: a(n) = a(n-1) +5*a(n-3) -5*a(n-4) +a(n-5) -2*a(n-6) +2*a(n-7) -2*a(n-8) -8*a(n-9) +5*a(n-10) -10*a(n-11) +10*a(n-12) +a(n-13) +2*a(n-14) +7*a(n-15) +a(n-17) +a(n-18) for n>19. %e A299446 Some solutions for n=5 %e A299446 ..0..0..0. .0..0..0. .0..1..0. .0..1..1. .0..0..1. .0..1..1. .0..0..0 %e A299446 ..0..0..0. .0..0..0. .0..1..0. .0..1..1. .0..0..1. .0..1..1. .0..0..0 %e A299446 ..0..0..0. .1..1..1. .0..0..0. .1..1..1. .1..1..1. .1..1..1. .0..0..0 %e A299446 ..0..0..0. .1..1..1. .0..1..0. .0..1..1. .1..1..0. .1..0..0. .1..1..1 %e A299446 ..0..0..0. .1..1..1. .0..1..0. .0..1..1. .1..1..0. .1..0..0. .1..1..1 %Y A299446 Cf. A299451. %K A299446 nonn %O A299446 1,1 %A A299446 _R. H. Hardin_, Feb 10 2018