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 A189259 #7 Jul 22 2025 11:38:29 %S A189259 12,144,1156,8900,65760,481552,3510380,25556548,185975588,1353139492, %T A189259 9844797788,71624858188,521097138012,3791166287372,27582062117196, %U A189259 200669125155708,1459937829727116,10621556383444668,77275523001250188 %N A189259 Number of nX4 binary arrays without the pattern 0 0 1 diagonally, antidiagonally or horizontally. %C A189259 Column 4 of A189264 %H A189259 R. H. Hardin, <a href="/A189259/b189259.txt">Table of n, a(n) for n = 1..200</a> %F A189259 Empirical: a(n) = 9*a(n-1) -9*a(n-2) -27*a(n-3) +62*a(n-4) -522*a(n-5) +730*a(n-6) +2202*a(n-7) -3620*a(n-8) +5768*a(n-9) -7920*a(n-10) -45696*a(n-11) +71680*a(n-12) +75424*a(n-13) -146112*a(n-14) +13984*a(n-15) +51072*a(n-16) -17024*a(n-17) for n>18 %e A189259 Some solutions for 4X3 %e A189259 ..0..1..0....1..1..1....0..1..0....1..1..1....0..0..0....1..1..0....1..0..0 %e A189259 ..1..1..1....0..1..0....1..1..1....0..1..0....1..1..0....1..1..1....0..1..1 %e A189259 ..1..1..1....1..1..1....1..1..0....1..1..1....0..0..0....1..1..0....0..1..0 %e A189259 ..0..1..1....0..1..1....1..1..0....0..0..1....1..1..0....0..1..1....0..0..0 %K A189259 nonn %O A189259 1,1 %A A189259 _R. H. Hardin_ Apr 19 2011