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 A302473 #4 Apr 08 2018 10:17:14 %S A302473 0,11,49,203,955,4556,21843,103319,491073,2332753,11082938,52648987, %T A302473 250106679,1188163911,5644397853,26814116700,127381683511, %U A302473 605134192403,2874722191055,13656526930929,64876076932622,308197362006435 %N A302473 Number of 3Xn 0..1 arrays with every element equal to 1, 2, 3 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302473 Row 3 of A302472. %H A302473 R. H. Hardin, <a href="/A302473/b302473.txt">Table of n, a(n) for n = 1..210</a> %F A302473 Empirical: a(n) = a(n-1) +17*a(n-2) +15*a(n-3) -33*a(n-4) -62*a(n-5) -148*a(n-6) -116*a(n-7) +343*a(n-8) +429*a(n-9) +269*a(n-10) +191*a(n-11) -415*a(n-12) -534*a(n-13) -468*a(n-14) -436*a(n-15) -132*a(n-16) -72*a(n-17) -8*a(n-18) +8*a(n-19) for n>21 %e A302473 Some solutions for n=5 %e A302473 ..0..0..1..1..1. .0..1..0..0..1. .0..0..0..1..1. .0..1..1..0..0 %e A302473 ..1..1..0..0..0. .0..0..1..1..0. .0..0..1..0..1. .1..0..0..0..0 %e A302473 ..1..0..0..1..1. .0..0..0..0..1. .1..1..1..0..0. .0..1..1..1..1 %Y A302473 Cf. A302472. %K A302473 nonn %O A302473 1,2 %A A302473 _R. H. Hardin_, Apr 08 2018