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 A207252 #7 Jul 22 2025 20:12:46 %S A207252 12,144,636,3560,18688,101036,541380,2906592,15585680,83611228, %T A207252 448508160,2406031628,12906861916,69237527840,371416568460, %U A207252 1992423747700,10688138114240,57335348257076,307569175706760,1649921069864080 %N A207252 Number of nX6 0..1 arrays avoiding 0 0 1 and 1 0 1 horizontally and 0 1 0 and 1 0 1 vertically. %C A207252 Column 6 of A207254 %H A207252 R. H. Hardin, <a href="/A207252/b207252.txt">Table of n, a(n) for n = 1..210</a> %F A207252 Empirical: a(n) = 3*a(n-1) +9*a(n-2) +4*a(n-3) +58*a(n-4) +117*a(n-5) +100*a(n-6) +160*a(n-7) +169*a(n-8) +74*a(n-9) -12*a(n-10) -67*a(n-11) -26*a(n-12) +6*a(n-13) +3*a(n-14) +3*a(n-15) -a(n-16) %e A207252 Some solutions for n=4 %e A207252 ..0..1..1..1..0..0....0..1..1..0..0..0....0..1..1..0..0..0....0..0..0..0..0..0 %e A207252 ..1..0..0..0..0..0....0..0..0..0..0..0....0..1..0..0..0..0....1..1..0..0..0..0 %e A207252 ..1..0..0..0..0..0....1..0..0..0..0..0....1..0..0..0..0..0....1..1..0..0..0..0 %e A207252 ..0..1..1..0..0..0....1..0..0..0..0..0....1..0..0..0..0..0....0..1..1..0..0..0 %K A207252 nonn %O A207252 1,1 %A A207252 _R. H. Hardin_ Feb 16 2012