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 A207183 #7 Jul 22 2025 20:05:33 %S A207183 12,144,1171,11227,105836,981850,9196215,85977231,803283624, %T A207183 7509476422,70190937945,656058072353,6132248125196,57318047597584, %U A207183 535750978547941,5007668680211309,46806669029193682,437501879260273952 %N A207183 Number of 4Xn 0..1 arrays avoiding 0 0 0 horizontally and 0 1 0 vertically. %C A207183 Row 4 of A207182 %H A207183 R. H. Hardin, <a href="/A207183/b207183.txt">Table of n, a(n) for n = 1..210</a> %F A207183 Empirical: a(n) = 4*a(n-1) +26*a(n-2) +217*a(n-3) +103*a(n-4) +85*a(n-5) -4044*a(n-6) +1053*a(n-7) -6517*a(n-8) +27058*a(n-9) -11158*a(n-10) +29024*a(n-11) -63148*a(n-12) +15300*a(n-13) -29296*a(n-14) +43157*a(n-15) +2016*a(n-16) +4274*a(n-17) -7152*a(n-18) -147*a(n-19) -45*a(n-20) +375*a(n-21) %e A207183 Some solutions for n=4 %e A207183 ..0..0..1..0....1..1..1..1....1..1..1..1....0..1..1..1....1..0..0..1 %e A207183 ..0..1..1..0....1..1..1..1....1..1..0..0....0..0..1..1....0..1..1..0 %e A207183 ..1..1..1..0....1..1..1..1....0..0..1..1....1..0..0..1....1..1..1..1 %e A207183 ..1..1..0..0....1..1..1..1....1..1..1..1....1..1..1..1....1..0..1..1 %K A207183 nonn %O A207183 1,1 %A A207183 _R. H. Hardin_ Feb 15 2012