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 A188990 #7 Jul 22 2025 11:30:52 %S A188990 54,2916,89744,2613530,72609144,2002277608,55080396536,1515192856324, %T A188990 41677443278252,1146393385863412,31532963467317340,867353027986156300, %U A188990 23857611484854924172,656232939488766364764,18050493852378599289948 %N A188990 Number of nX7 binary arrays without the pattern 0 0 1 antidiagonally or horizontally. %C A188990 Column 7 of A188992 %H A188990 R. H. Hardin, <a href="/A188990/b188990.txt">Table of n, a(n) for n = 1..200</a> %F A188990 Empirical: a(n) = 35*a(n-1) -175*a(n-2) -1169*a(n-3) +8904*a(n-4) -5838*a(n-5) -78636*a(n-6) +390264*a(n-7) -535812*a(n-8) -1472012*a(n-9) +4073408*a(n-10) -2206456*a(n-11) +439232*a(n-12) -2614848*a(n-13) +1784672*a(n-14) +415680*a(n-15) +176768*a(n-16) -281856*a(n-17) -92160*a(n-18) for n>22 %e A188990 Some solutions for 3X7 %e A188990 ..1..1..1..1..0..1..1....0..1..0..1..0..1..0....1..1..0..1..1..1..1 %e A188990 ..0..1..1..1..1..1..1....0..1..1..1..0..1..1....0..1..1..1..0..1..0 %e A188990 ..1..0..1..0..1..0..0....1..1..0..0..0..0..0....0..1..0..0..0..0..0 %K A188990 nonn %O A188990 1,1 %A A188990 _R. H. Hardin_ Apr 15 2011