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 A298082 #4 Jan 12 2018 08:59:05 %S A298082 0,3,0,3,1,7,18,52,144,405,1124,3113,8688,24346,68385,192524,542537, %T A298082 1529960,4316175,12178973,34370746,97008377,273813995,772895361, %U A298082 2181712563,6158599574,17384869895,49075425772,138534755824,391070202040 %N A298082 Number of nX3 0..1 arrays with every element equal to 2, 3, 5 or 6 king-move adjacent elements, with upper left element zero. %C A298082 Column 3 of A298087. %H A298082 R. H. Hardin, <a href="/A298082/b298082.txt">Table of n, a(n) for n = 1..210</a> %F A298082 Empirical: a(n) = 3*a(n-1) +2*a(n-2) -4*a(n-3) -11*a(n-4) +a(n-5) +15*a(n-6) +7*a(n-7) +a(n-8) -24*a(n-9) -39*a(n-10) +13*a(n-11) +32*a(n-12) +8*a(n-13) +5*a(n-14) -2*a(n-15) -2*a(n-16) for n>17 %e A298082 Some solutions for n=7 %e A298082 ..0..0..1. .0..0..1. .0..1..1. .0..0..0. .0..0..1. .0..1..1. .0..0..0 %e A298082 ..0..1..1. .0..1..1. .0..0..1. .1..0..1. .0..1..1. .0..0..1. .1..0..1 %e A298082 ..0..1..0. .0..1..0. .1..0..1. .1..1..1. .0..1..0. .1..0..1. .1..1..1 %e A298082 ..0..0..0. .1..0..0. .1..1..1. .1..0..1. .0..0..0. .1..1..0. .1..0..1 %e A298082 ..0..1..0. .1..1..1. .1..0..1. .0..0..0. .0..1..0. .0..0..0. .0..0..0 %e A298082 ..0..1..1. .1..0..1. .0..0..1. .1..1..1. .1..1..0. .0..1..0. .0..1..0 %e A298082 ..0..0..1. .0..0..0. .0..1..1. .1..1..1. .1..0..0. .1..1..1. .1..1..1 %Y A298082 Cf. A298087. %K A298082 nonn %O A298082 1,2 %A A298082 _R. H. Hardin_, Jan 12 2018