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 A299656 #4 Feb 15 2018 14:45:45 %S A299656 4,32,227,1642,11888,86123,624007,4521433,32761769,237388544, %T A299656 1720095182,12463651182,90310472508,654381403622,4741587670337, %U A299656 34357109680119,248948467884508,1803857782078629,13070588164990173,94708283921766839 %N A299656 Number of nX3 0..1 arrays with every element equal to 0, 1, 2, 3, 4, 5 or 7 king-move adjacent elements, with upper left element zero. %C A299656 Column 3 of A299661. %H A299656 R. H. Hardin, <a href="/A299656/b299656.txt">Table of n, a(n) for n = 1..210</a> %F A299656 Empirical: a(n) = 7*a(n-1) +3*a(n-2) -6*a(n-3) -18*a(n-4) -15*a(n-5) -17*a(n-6) -32*a(n-7) -12*a(n-8) %e A299656 Some solutions for n=5 %e A299656 ..0..0..1. .0..1..0. .0..1..0. .0..0..0. .0..0..1. .0..1..1. .0..1..1 %e A299656 ..0..1..0. .0..1..1. .0..0..1. .0..1..1. .0..0..1. .0..0..1. .1..0..1 %e A299656 ..1..1..0. .0..0..0. .1..0..0. .1..0..1. .0..1..1. .0..1..1. .0..1..1 %e A299656 ..0..0..1. .0..0..1. .0..1..1. .0..0..1. .0..0..1. .1..1..1. .1..0..0 %e A299656 ..0..0..1. .0..0..0. .0..0..1. .0..1..1. .1..0..0. .1..1..1. .0..1..1 %Y A299656 Cf. A299661. %K A299656 nonn %O A299656 1,1 %A A299656 _R. H. Hardin_, Feb 15 2018