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 A207995 #12 Nov 23 2015 05:52:48 %S A207995 16,243,3891,63267,1034073,16932816,277458045,4547477370,74538711609, %T A207995 1221819475953,20027983390866,328298744831580,5381481886580865, %U A207995 88213445048426316,1445998260462433698,23702862077090281716 %N A207995 Number of nX6 0..2 arrays with new values 0..2 introduced in row major order and no element equal to any horizontal or vertical neighbor (colorings ignoring permutations of colors). %C A207995 Column 6 of A207997. %H A207995 R. H. Hardin, <a href="/A207995/b207995.txt">Table of n, a(n) for n = 1..210</a> %H A207995 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (30,-291,1278,-2901,3519,-2152,516). %F A207995 a(n) = 30*a(n-1) -291*a(n-2) +1278*a(n-3) -2901*a(n-4) +3519*a(n-5) -2152*a(n-6) +516*a(n-7). %F A207995 G.f.: -x*(16-237*x+1257*x^2-3198*x^3+4206*x^4-2736*x^5+688*x^6) / ( -1+30*x-291*x^2+1278*x^3-2901*x^4+3519*x^5-2152*x^6+516*x^7 ). - _R. J. Mathar_, Nov 23 2015 %e A207995 Some solutions for n=4 %e A207995 ..0..1..2..0..2..0....0..1..2..0..1..2....0..1..2..0..1..0....0..1..2..0..1..2 %e A207995 ..1..0..1..2..0..1....2..0..1..2..0..1....2..0..1..2..0..1....1..0..1..2..0..1 %e A207995 ..0..1..0..1..2..0....0..1..2..1..2..0....1..2..0..1..2..0....2..1..2..0..1..2 %e A207995 ..1..0..1..2..0..2....1..2..1..2..1..2....2..0..1..0..1..2....0..2..0..1..2..1 %K A207995 nonn %O A207995 1,1 %A A207995 _R. H. Hardin_, Feb 22 2012