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 A202399 #7 Jul 22 2025 16:34:01 %S A202399 126,441,1785,7225,27880,107584,422136,1656369,6459453,25190361, %T A202399 98462742,384865924,1503033070,5869858225,22931405805,89584680249, %U A202399 349930588752,1366878986496,5339482693488,20857790423089,81475946359561 %N A202399 Number of (n+2)X3 binary arrays avoiding patterns 000 and 010 in rows and columns. %C A202399 Column 1 of A202406 %H A202399 R. H. Hardin, <a href="/A202399/b202399.txt">Table of n, a(n) for n = 1..210</a> %F A202399 Empirical: a(n) = 2*a(n-1) -a(n-2) +18*a(n-3) +44*a(n-4) +38*a(n-5) +80*a(n-6) -80*a(n-8) -38*a(n-9) -44*a(n-10) -18*a(n-11) +a(n-12) -2*a(n-13) +a(n-14) %e A202399 Some solutions for n=5 %e A202399 ..1..0..1....1..1..1....1..1..0....0..1..1....0..1..1....1..1..1....1..1..0 %e A202399 ..1..1..0....0..1..1....1..1..1....1..0..0....0..1..1....0..1..1....1..1..1 %e A202399 ..0..1..1....1..1..1....1..0..1....1..0..1....1..1..1....1..0..0....0..0..1 %e A202399 ..0..1..1....1..1..1....1..0..1....1..1..1....1..0..1....1..0..1....1..1..1 %e A202399 ..1..1..1....0..0..1....1..1..1....0..1..1....1..0..0....0..1..1....1..1..1 %e A202399 ..1..0..1....1..0..1....0..1..1....1..1..0....0..1..1....1..1..0....1..0..1 %e A202399 ..1..1..0....1..1..0....0..0..1....1..0..0....0..1..1....1..0..1....0..1..1 %K A202399 nonn %O A202399 1,1 %A A202399 _R. H. Hardin_ Dec 19 2011