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 A207341 #7 Jul 22 2025 20:18:18 %S A207341 6,36,84,292,912,2812,8928,28152,87972,277292,872524,2738692,8615772, %T A207341 27093728,85142632,267722916,841747760,2646047052,8319199464, %U A207341 26155059448,82225749476,258510349884,812729058372,2555098454212,8032934120092 %N A207341 Number of nX3 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 0 and 1 1 1 vertically. %C A207341 Column 3 of A207346 %H A207341 R. H. Hardin, <a href="/A207341/b207341.txt">Table of n, a(n) for n = 1..210</a> %F A207341 Empirical: a(n) = 4*a(n-2) +16*a(n-3) +13*a(n-4) -10*a(n-5) -17*a(n-6) -8*a(n-7) +2*a(n-8) -2*a(n-9) -a(n-10) for n>13 %e A207341 Some solutions for n=4 %e A207341 ..0..0..1....1..1..0....1..0..1....1..0..0....1..0..1....1..1..1....0..0..1 %e A207341 ..1..1..0....1..1..1....1..1..0....0..0..1....1..0..1....0..0..1....1..0..1 %e A207341 ..0..0..1....0..0..1....0..1..0....1..1..1....0..1..0....0..1..0....0..1..0 %e A207341 ..0..0..1....1..1..0....0..0..1....0..1..0....0..0..1....1..0..0....1..1..1 %K A207341 nonn %O A207341 1,1 %A A207341 _R. H. Hardin_ Feb 17 2012