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 A301792 #4 Mar 26 2018 16:43:28 %S A301792 4,13,12,17,25,38,59,93,148,237,381,614,991,1601,2588,4185,6769,10950, %T A301792 17715,28661,46372,75029,121397,196422,317815,514233,832044,1346273, %U A301792 2178313,3524582,5702891,9227469,14930356,24157821,39088173,63245990 %N A301792 Number of 3Xn 0..1 arrays with every element equal to 0 or 1 horizontally or antidiagonally adjacent elements, with upper left element zero. %C A301792 Row 3 of A301790. %H A301792 R. H. Hardin, <a href="/A301792/b301792.txt">Table of n, a(n) for n = 1..210</a> %F A301792 Empirical: a(n) = 2*a(n-1) -a(n-3) for n>5 %e A301792 Some solutions for n=5 %e A301792 ..0..1..0..1..0. .0..0..1..1..0. .0..0..1..0..1. .0..1..0..0..1 %e A301792 ..1..0..1..0..1. .1..0..0..1..0. .1..0..1..0..0. .0..1..1..0..1 %e A301792 ..1..0..1..0..0. .1..1..0..1..0. .1..0..1..1..0. .0..0..1..0..0 %Y A301792 Cf. A301790. %K A301792 nonn %O A301792 1,1 %A A301792 _R. H. Hardin_, Mar 26 2018