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 A261375 #4 Aug 17 2015 08:29:32 %S A261375 60,82,202,424,869,1714,3778,7462,15888,31618,68245,135058,290195, %T A261375 575938,1238957,2455954,5282429,10475722,22530337,44674906,96090169, %U A261375 190539730,409810129,812624530,1747814377,3465775738,7454228289,14781184618 %N A261375 Number of (n+2)X(3+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00001011 00010101 or 01010101. %C A261375 Column 3 of A261380. %H A261375 R. H. Hardin, <a href="/A261375/b261375.txt">Table of n, a(n) for n = 1..210</a> %F A261375 Empirical: a(n) = a(n-2) +11*a(n-4) +13*a(n-6) -2*a(n-8) -2*a(n-10) +4*a(n-12) for n>17 %e A261375 Some solutions for n=4 %e A261375 ..0..0..1..0..1....0..1..0..0..0....1..0..1..0..1....0..1..0..1..0 %e A261375 ..0..1..0..1..0....1..0..1..0..1....0..0..0..1..0....1..0..1..0..1 %e A261375 ..1..0..1..0..1....0..1..0..1..0....1..0..1..0..0....0..1..0..1..0 %e A261375 ..0..1..0..1..0....1..0..1..0..1....0..1..0..1..0....1..0..1..0..1 %e A261375 ..1..0..1..0..1....0..1..0..1..0....0..0..1..0..1....0..1..0..0..0 %e A261375 ..0..1..0..0..0....0..0..1..0..1....0..1..0..1..0....0..0..1..0..1 %Y A261375 Cf. A261380. %K A261375 nonn %O A261375 1,1 %A A261375 _R. H. Hardin_, Aug 17 2015