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 A208007 #7 Jul 22 2025 21:06:05 %S A208007 2,4,4,6,16,6,9,36,36,9,14,81,92,81,14,22,196,221,221,196,22,35,484, %T A208007 618,536,618,484,35,56,1225,1690,1711,1711,1690,1225,56,90,3136,4861, %U A208007 4993,7016,4993,4861,3136,90,145,8100,13900,16742,24512,24512,16742,13900 %N A208007 T(n,k)=Number of nXk 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 1 1 and 1 1 0 vertically. %C A208007 Table starts %C A208007 ..2....4.....6.....9.....14......22.......35........56........90........145 %C A208007 ..4...16....36....81....196.....484.....1225......3136......8100......21025 %C A208007 ..6...36....92...221....618....1690.....4861.....13900.....40452.....117717 %C A208007 ..9...81...221...536...1711....4993....16742.....53411....182247.....608142 %C A208007 .14..196...618..1711...7016...24512...106503....411848...1787438....7238503 %C A208007 .22..484..1690..4993..24512...90232...486443...2001968..10846870...47911153 %C A208007 .35.1225..4861.16742.106503..486443..3569728..18874239.139219755..803098636 %C A208007 .56.3136.13900.53411.411848.2001968.18874239.101519408.989521860.5706548155 %H A208007 R. H. Hardin, <a href="/A208007/b208007.txt">Table of n, a(n) for n = 1..479</a> %e A208007 Some solutions for n=4 k=3 %e A208007 ..0..1..0....0..0..0....0..1..0....1..0..1....1..0..1....0..0..0....0..1..0 %e A208007 ..0..0..0....0..1..1....1..1..0....0..0..0....0..0..0....0..1..1....0..1..0 %e A208007 ..0..1..1....0..0..0....0..1..0....1..1..1....0..1..1....0..0..0....0..1..1 %e A208007 ..0..0..0....0..1..0....1..1..1....0..0..0....0..0..0....1..0..1....1..1..0 %Y A208007 Column 1 is A001611(n+2) %Y A208007 Column 2 is A207436 %Y A208007 Column 3 is A207559 %K A208007 nonn,tabl %O A208007 1,1 %A A208007 _R. H. Hardin_ Feb 22 2012