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 A189691 #7 Jul 22 2025 11:52:45 %S A189691 16,256,1723,11637,65297,370045,1999150,10867960,58328512,313915268, %T A189691 1683430923,9037137069,48464436537,259999868553,1394419535984, %U A189691 7479394198332,40114452013630,215155499724100,1153964519450151 %N A189691 Number of nX4 binary arrays without the pattern 0 0 1 diagonally, vertically or antidiagonally. %C A189691 Column 4 of A189696 %H A189691 R. H. Hardin, <a href="/A189691/b189691.txt">Table of n, a(n) for n = 1..200</a> %F A189691 Empirical: a(n) = 6*a(n-1) +9*a(n-2) -72*a(n-3) -15*a(n-4) +208*a(n-5) +249*a(n-6) -365*a(n-7) -957*a(n-8) +452*a(n-9) +841*a(n-10) +303*a(n-11) +1413*a(n-12) -2116*a(n-13) -3083*a(n-14) +2561*a(n-15) +1244*a(n-16) -148*a(n-17) +1056*a(n-18) -2105*a(n-19) -508*a(n-20) +1674*a(n-21) -720*a(n-22) -330*a(n-23) +592*a(n-24) -100*a(n-25) -120*a(n-26) +32*a(n-27) %e A189691 Some solutions for 3X4 %e A189691 ..0..0..0..0....1..1..0..1....0..0..1..0....1..1..0..1....1..1..1..0 %e A189691 ..1..1..1..1....1..1..1..1....1..1..1..1....0..1..0..1....0..0..0..0 %e A189691 ..1..0..1..1....0..0..1..0....0..1..1..1....0..0..0..0....1..0..1..0 %K A189691 nonn %O A189691 1,1 %A A189691 _R. H. Hardin_ Apr 25 2011