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 A188852 #7 Jul 22 2025 11:25:25 %S A188852 7,49,219,908,3642,14265,54914,209116,790202,2970663,11127947, %T A188852 41582147,155115627,577944508,2151567661,8005167634,29772011406, %U A188852 110693241831,411477718640,1529360380741,5683684052119,21121242014609,78485142931206 %N A188852 Number of 3Xn binary arrays without the pattern 0 0 1 vertically, antidiagonally or horizontally. %C A188852 Row 3 of A188851 %H A188852 R. H. Hardin, <a href="/A188852/b188852.txt">Table of n, a(n) for n = 1..200</a> %F A188852 Empirical: a(n) = 6*a(n-1) +a(n-2) -53*a(n-3) +26*a(n-4) +199*a(n-5) -95*a(n-6) -408*a(n-7) +113*a(n-8) +470*a(n-9) -31*a(n-10) -286*a(n-11) -14*a(n-12) +92*a(n-13) +8*a(n-14) -15*a(n-15) -a(n-16) +a(n-17) for n>18 %e A188852 Some solutions for 3X3 %e A188852 ..1..0..1....0..1..0....1..0..1....0..1..1....0..1..1....1..0..1....0..1..1 %e A188852 ..0..1..1....0..1..1....0..1..0....1..1..1....0..0..0....0..1..1....1..0..1 %e A188852 ..0..1..0....0..0..0....0..1..1....0..1..0....0..0..0....1..0..1....1..1..0 %K A188852 nonn %O A188852 1,1 %A A188852 _R. H. Hardin_ Apr 12 2011