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 A206467 #10 Jun 16 2018 16:03:00 %S A206467 441,11025,110889,1896129,23707161,356190129,4803737481,69030731169, %T A206467 955680252921,13523866505361,188928681187689,2659384141993089, %U A206467 37267791691450329,523625523775949169,7345838128808607561 %N A206467 Number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock having zero permanent. %C A206467 Column 3 of A206472. %H A206467 R. H. Hardin, <a href="/A206467/b206467.txt">Table of n, a(n) for n = 1..210</a> %F A206467 Empirical: a(n) = 15*a(n-1) + 54*a(n-2) - 1116*a(n-3) + 1728*a(n-4) + 10368*a(n-5) - 20736*a(n-6). %F A206467 Empirical g.f.: 9*x*(49 + 490*x - 8700*x^2 + 14400*x^3 + 91008*x^4 - 186624*x^5) / ((1 - 21*x + 108*x^2 - 144*x^3)*(1 + 6*x - 36*x^2 - 144*x^3)). - _Colin Barker_, Jun 16 2018 %e A206467 Some solutions for n=4: %e A206467 2 2 2 1 2 2 0 0 0 1 0 1 1 2 0 0 0 0 2 0 %e A206467 0 0 0 0 0 0 0 1 0 2 0 2 0 0 0 2 0 0 2 0 %e A206467 1 2 1 0 2 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 %e A206467 0 0 0 0 2 0 0 1 0 1 0 1 0 0 1 0 2 2 1 0 %e A206467 2 1 2 1 2 0 0 2 0 1 0 1 1 0 2 0 0 0 0 0 %Y A206467 Cf. A206472. %K A206467 nonn %O A206467 1,1 %A A206467 _R. H. Hardin_, Feb 08 2012