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 A188821 #8 Apr 30 2018 08:56:18 %S A188821 64,441,1296,2704,4624,7056,10000,13456,17424,21904,26896,32400,38416, %T A188821 44944,51984,59536,67600,76176,85264,94864,104976,115600,126736, %U A188821 138384,150544,163216,176400,190096,204304,219024,234256,250000,266256,283024 %N A188821 Number of n X 6 binary arrays without the pattern 0 1 diagonally or antidiagonally. %C A188821 Column 6 of A188824. %H A188821 R. H. Hardin, <a href="/A188821/b188821.txt">Table of n, a(n) for n = 1..200</a> %F A188821 Empirical: a(n) = 256*n^2 - 384*n + 144 for n>2. %F A188821 Conjectures from _Colin Barker_, Apr 30 2018: (Start) %F A188821 G.f.: x*(64 + 249*x + 165*x^2 + 75*x^3 - 41*x^4) / (1 - x)^3. %F A188821 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>5. %F A188821 (End) %e A188821 Some solutions for 3 X 6: %e A188821 ..0..1..1..1..1..1....1..1..1..1..1..1....1..0..1..1..1..1....0..1..0..1..1..1 %e A188821 ..0..0..1..0..1..0....0..1..1..1..1..1....0..1..0..1..0..1....1..0..1..0..1..1 %e A188821 ..0..0..0..1..0..0....0..0..1..1..1..1....1..0..1..0..1..0....0..1..0..0..0..0 %Y A188821 Cf. A188824. %K A188821 nonn %O A188821 1,1 %A A188821 _R. H. Hardin_, Apr 11 2011