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 A207947 #7 Jul 22 2025 21:02:15 %S A207947 16,256,1296,8836,55696,362404,2334784,15069924,97180164,626901444, %T A207947 4043942464,26086772196,168278807524,1085522269456,7002416779264, %U A207947 45170765646400,291384831720004,1879647527429604,12125115459266404 %N A207947 Number of nX6 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 1 0 and 1 0 1 vertically. %C A207947 Column 6 of A207949 %H A207947 R. H. Hardin, <a href="/A207947/b207947.txt">Table of n, a(n) for n = 1..210</a> %F A207947 Empirical: a(n) = 5*a(n-1) +7*a(n-2) +a(n-3) +76*a(n-4) +105*a(n-5) -4*a(n-6) -115*a(n-7) -119*a(n-8) +a(n-9) +29*a(n-10) +41*a(n-11) -8*a(n-12) -4*a(n-14) +a(n-15) %e A207947 Some solutions for n=4 %e A207947 ..1..1..1..1..0..1....0..0..0..0..0..0....0..0..0..0..0..0....1..0..1..0..1..0 %e A207947 ..0..1..0..1..0..1....1..1..1..0..1..0....1..0..1..0..0..0....1..1..0..0..0..0 %e A207947 ..0..0..0..0..0..0....1..1..1..0..1..0....1..1..1..1..0..0....1..1..0..1..0..1 %e A207947 ..0..0..0..0..0..0....1..0..1..0..0..0....1..1..0..1..0..0....1..1..1..1..0..1 %K A207947 nonn %O A207947 1,1 %A A207947 _R. H. Hardin_ Feb 21 2012