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 A206468 #7 Jul 22 2025 19:27:39 %S A206468 1849,106891,1896129,68352739,1693734025,52552339515,1457044540561, %T A206468 43214597865811,1240051361495769,36294544907153707, %U A206468 1052106476736321889,30674877583244503491,891844034416624515625,25973093752500918767899 %N A206468 Number of (n+1)X5 0..2 arrays with every 2X2 subblock having zero permanent. %C A206468 Column 4 of A206472 %H A206468 R. H. Hardin, <a href="/A206468/b206468.txt">Table of n, a(n) for n = 1..210</a> %F A206468 Empirical: a(n) = 39*a(n-1) -11348*a(n-3) +76272*a(n-4) +429792*a(n-5) -3994496*a(n-6) +37171200*a(n-8) -43614208*a(n-9) %e A206468 Some solutions for n=4 %e A206468 ..1..1..1..2..1....0..0..2..1..1....0..0..2..2..2....2..0..0..1..1 %e A206468 ..0..0..0..0..0....2..0..0..0..0....1..0..0..0..0....2..0..0..0..0 %e A206468 ..1..2..0..1..2....2..0..1..2..1....1..0..0..2..1....0..0..2..2..0 %e A206468 ..0..0..0..0..0....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0 %e A206468 ..0..1..2..0..1....1..0..1..2..0....2..1..0..0..2....2..2..2..1..2 %K A206468 nonn %O A206468 1,1 %A A206468 _R. H. Hardin_ Feb 08 2012