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 A218065 #9 Jul 23 2018 14:23:43 %S A218065 4,6,18,42,108,268,676,1694,4258,10690,26852,67436,169372,425382, %T A218065 1068370,2683258,6739132,16925644,42509556,106764750,268144706, %U A218065 673458066,1691421684,4248085292,10669266476,26796365718,67300335730,169027965834 %N A218065 Number of 2 X n arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random 0..1 2 X n array. %C A218065 Row 2 of A218064. %H A218065 R. H. Hardin, <a href="/A218065/b218065.txt">Table of n, a(n) for n = 1..210</a> %F A218065 Empirical: a(n) = a(n-1) + 4*a(n-2) + a(n-3) - 3*a(n-4) - 2*a(n-5). %F A218065 Empirical g.f.: 2*x*(2 + x - 2*x^2 - 2*x^3) / ((1 - x)*(1 + x)*(1 - x - 3*x^2 - 2*x^3)). - _Colin Barker_, Jul 23 2018 %e A218065 Some solutions for n=3: %e A218065 ..1..1..1....0..0..0....0..0..0....1..0..0....1..0..0....1..0..0....0..0..0 %e A218065 ..1..1..1....0..0..1....0..1..1....0..0..1....1..0..0....1..0..1....0..0..0 %Y A218065 Cf. A218064. %K A218065 nonn %O A218065 1,1 %A A218065 _R. H. Hardin_, Oct 19 2012