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 A189191 #7 Jul 22 2025 11:36:31 %S A189191 16,256,2032,15326,101628,657028,4109278,25421672,155713446,949556490, %T A189191 5771152218,35012940148,212158079476,1284620610228,7774639010740, %U A189191 47038657576938,284540271729956,1720987141305056,10408196505797294 %N A189191 Number of nX4 binary arrays without the pattern 0 0 1 vertically or antidiagonally. %C A189191 Column 4 of A189196 %H A189191 R. H. Hardin, <a href="/A189191/b189191.txt">Table of n, a(n) for n = 1..200</a> %F A189191 Empirical: a(n) = 13*a(n-1) -24*a(n-2) -309*a(n-3) +1139*a(n-4) +2904*a(n-5) -15708*a(n-6) -13388*a(n-7) +114908*a(n-8) +27510*a(n-9) -517862*a(n-10) +10696*a(n-11) +1525375*a(n-12) -199987*a(n-13) -2999240*a(n-14) +537335*a(n-15) +3938119*a(n-16) -825688*a(n-17) -3403810*a(n-18) +826898*a(n-19) +1870596*a(n-20) -531896*a(n-21) -607828*a(n-22) +201144*a(n-23) +99904*a(n-24) -37536*a(n-25) -5568*a(n-26) +2304*a(n-27) %e A189191 Some solutions for 3X4 %e A189191 ..1..1..1..0....1..1..1..1....0..1..1..1....0..0..0..0....0..1..0..1 %e A189191 ..1..1..1..1....1..0..0..0....1..0..1..1....0..1..0..0....1..1..1..0 %e A189191 ..1..0..1..1....0..1..1..0....0..0..0..0....0..0..0..0....1..1..0..0 %K A189191 nonn %O A189191 1,1 %A A189191 _R. H. Hardin_ Apr 18 2011