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 A261376 #4 Aug 17 2015 08:30:12 %S A261376 97,157,424,1040,2282,5254,12500,28885,66332,154413,358786,830309, %T A261376 1923846,4465820,10349526,23993883,55620850,129004265,298983410, %U A261376 693371845,1607151330,3727183505,8638778942,20034575762,46436324264 %N A261376 Number of (n+2)X(4+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00001011 00010101 or 01010101. %C A261376 Column 4 of A261380. %H A261376 R. H. Hardin, <a href="/A261376/b261376.txt">Table of n, a(n) for n = 1..210</a> %F A261376 Empirical: a(n) = a(n-2) +18*a(n-4) +32*a(n-6) -7*a(n-8) -33*a(n-10) +13*a(n-12) +25*a(n-14) -28*a(n-16) +9*a(n-18) -a(n-20) for n>22 %e A261376 Some solutions for n=4 %e A261376 ..1..0..1..0..1..0....1..0..0..0..1..0....1..0..1..0..1..0....0..1..0..1..0..0 %e A261376 ..0..1..0..1..0..1....0..1..0..1..0..1....0..1..0..1..0..0....0..0..1..0..1..0 %e A261376 ..1..0..1..0..0..0....1..0..1..0..1..0....1..0..1..0..1..0....0..1..0..1..0..1 %e A261376 ..0..0..0..1..0..1....0..1..0..1..0..1....0..1..0..1..0..1....1..0..1..0..1..0 %e A261376 ..1..0..1..0..1..0....0..0..1..0..0..0....1..0..1..0..1..0....0..1..0..0..0..1 %e A261376 ..0..1..0..1..0..1....0..1..0..1..0..1....0..1..0..1..0..1....1..0..1..0..1..0 %Y A261376 Cf. A261380. %K A261376 nonn %O A261376 1,1 %A A261376 _R. H. Hardin_, Aug 17 2015