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 A207741 #7 Jul 22 2025 20:45:25 %S A207741 2,4,4,6,16,6,9,36,36,9,15,81,114,81,14,25,225,361,387,196,22,40,625, %T A207741 1425,1849,1414,484,35,64,1600,5625,10535,10201,5302,1225,56,104,4096, %U A207741 20550,60025,86355,58081,20265,3136,90,169,10816,75076,327075,731025 %N A207741 T(n,k)=Number of nXk 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 0 0 vertically. %C A207741 Table starts %C A207741 ..2....4.....6.......9.......15.........25..........40............64 %C A207741 ..4...16....36......81......225........625........1600..........4096 %C A207741 ..6...36...114.....361.....1425.......5625.......20550.........75076 %C A207741 ..9...81...387....1849....10535......60025......327075.......1782225 %C A207741 .14..196..1414...10201....86355.....731025.....5959350......48580900 %C A207741 .22..484..5302...58081...733363....9259849...113534330....1392036100 %C A207741 .35.1225.20265..335241..6349893..120275089..2215586241...40813292529 %C A207741 .56.3136.78120.1946025.55343835.1573946929.43590708750.1207251562500 %H A207741 R. H. Hardin, <a href="/A207741/b207741.txt">Table of n, a(n) for n = 1..391</a> %e A207741 Some solutions for n=4 k=3 %e A207741 ..1..1..1....0..1..1....0..1..1....0..0..1....1..1..1....0..1..1....1..1..0 %e A207741 ..1..1..1....1..1..0....1..0..0....1..0..0....1..1..0....1..0..1....1..0..1 %e A207741 ..1..1..1....1..1..1....1..1..1....0..0..1....1..0..1....0..1..1....1..1..0 %e A207741 ..1..1..1....1..0..1....1..1..0....1..0..1....1..1..1....1..1..0....0..1..1 %Y A207741 Column 1 is A001611(n+2) %Y A207741 Column 2 is A207436 %Y A207741 Column 3 is A207712 %Y A207741 Row 1 is A006498(n+2) %Y A207741 Row 2 is A189145(n+2) %Y A207741 Row 3 is A207427 %K A207741 nonn,tabl %O A207741 1,1 %A A207741 _R. H. Hardin_ Feb 19 2012