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 A208422 #7 Jul 22 2025 21:21:14 %S A208422 13,169,611,3835,18395,100113,512525,2702193,14044303,73505289, %T A208422 383392451,2003126697,10456915209,54611619153,285148941623, %U A208422 1489042615021,7775302008851,40601362677837,212010307642445,1107075047855985 %N A208422 Number of 5Xn 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 0 and 0 1 1 vertically. %C A208422 Row 5 of A208420 %H A208422 R. H. Hardin, <a href="/A208422/b208422.txt">Table of n, a(n) for n = 1..210</a> %F A208422 Empirical: a(n) = a(n-1) +23*a(n-2) +11*a(n-3) -83*a(n-4) -21*a(n-5) +96*a(n-6) +12*a(n-7) -42*a(n-8) -2*a(n-9) +6*a(n-10) %e A208422 Some solutions for n=4 %e A208422 ..1..1..0..1....1..1..1..1....0..1..1..0....0..1..1..1....1..1..0..1 %e A208422 ..0..1..0..0....1..0..1..0....0..1..0..0....1..0..1..1....1..0..1..0 %e A208422 ..0..1..1..0....1..1..1..1....1..0..1..1....0..1..0..1....0..1..0..0 %e A208422 ..1..1..0..1....1..0..1..0....0..1..0..0....1..0..1..0....1..0..1..1 %e A208422 ..0..1..1..0....0..1..1..0....1..0..1..1....0..1..0..0....0..1..0..0 %K A208422 nonn %O A208422 1,1 %A A208422 _R. H. Hardin_ Feb 26 2012