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 A188608 #7 Jul 22 2025 11:17:34 %S A188608 7,49,211,847,3282,12405,45860,167525,605878,2177496,7787333,27757367, %T A188608 98687854,350247594,1241371867,4395505741,15552531864,55000200159, %U A188608 194426956404,687105218857,2427709127594,8576325199050,30293865359314 %N A188608 Number of 3Xn binary arrays without the pattern 1 1 0 diagonally, vertically, antidiagonally or horizontally. %C A188608 Row 3 of A188607 %H A188608 R. H. Hardin, <a href="/A188608/b188608.txt">Table of n, a(n) for n = 1..200</a> %F A188608 Empirical: a(n) = 6*a(n-1) + a(n-2) - 56*a(n-3) + 38*a(n-4) + 201*a(n-5) - 139*a(n-6) - 386*a(n-7) + 109*a(n-8) + 450*a(n-9) + 195*a(n-10) - 288*a(n-11) - 391*a(n-12) + 11*a(n-13) + 219*a(n-14) + 110*a(n-15) - 13*a(n-16) - 53*a(n-17) - 21*a(n-18) + 5*a(n-19) + 3*a(n-20) for n>21 %e A188608 Some solutions for 3X3 %e A188608 ..0..0..0....0..1..1....1..0..1....0..0..1....0..0..0....0..0..1....0..0..1 %e A188608 ..0..0..0....0..0..0....1..0..0....0..0..0....0..1..1....0..0..1....1..0..0 %e A188608 ..0..1..0....0..0..0....1..0..1....0..0..0....0..0..1....1..0..1....1..0..1 %K A188608 nonn %O A188608 1,1 %A A188608 _R. H. Hardin_ Apr 05 2011