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 A188826 #9 Apr 30 2018 14:11:27 %S A188826 16,25,81,256,841,2704,8836,28561,93025,301401,980100,3179089, %T A188826 10329796,33524100,108889225,353477601,1147922161,3726858304, %U A188826 12101980081,39292754176,127587553636,414263438689,1345129081209,4367552437161 %N A188826 Number of 4 X n binary arrays without the pattern 0 1 diagonally or antidiagonally. %C A188826 Row 4 of A188824. %H A188826 R. H. Hardin, <a href="/A188826/b188826.txt">Table of n, a(n) for n = 1..200</a> %F A188826 Empirical: a(n) = 3*a(n-1) + 5*a(n-2) - 15*a(n-3) + 3*a(n-4) + 5*a(n-5) - a(n-6) for n>7. %F A188826 Empirical g.f.: x*(16 - 23*x - 74*x^2 + 128*x^3 - 5*x^4 - 39*x^5 + 7*x^6) / ((1 - 5*x + 6*x^2 - x^3)*(1 + 2*x - x^2 - x^3)). - _Colin Barker_, Apr 30 2018 %e A188826 Some solutions for 4 X 3: %e A188826 ..0..1..1....0..1..0....1..1..1....0..1..0....1..1..0....0..1..0....1..1..1 %e A188826 ..0..0..1....1..0..1....1..1..1....0..0..0....1..0..1....1..0..0....1..1..1 %e A188826 ..0..0..0....0..0..0....0..0..1....0..0..0....0..1..0....0..0..0....1..1..1 %e A188826 ..0..0..0....0..0..0....0..0..0....0..0..0....0..0..1....0..0..0....0..1..1 %Y A188826 Cf. A188824. %K A188826 nonn %O A188826 1,1 %A A188826 _R. H. Hardin_, Apr 11 2011