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 A207600 #7 May 11 2023 14:26:07 %S A207600 6,36,90,225,825,3025,9240,28224,93912,312481,997815,3186225,10377990, %T A207600 33802596,109041570,351750025,1140060185,3695059369,11948292720, %U A207600 38635833600,125075648880,404906960329,1310059883431,4238645087209 %N A207600 Number of 3 X n 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 0 1 vertically. %C A207600 Row 3 of A207599. %H A207600 R. H. Hardin, <a href="/A207600/b207600.txt">Table of n, a(n) for n = 1..210</a> %F A207600 Empirical: a(n) = a(n-1) -2*a(n-2) +11*a(n-3) +43*a(n-4) +34*a(n-5) +108*a(n-6) -216*a(n-8) -136*a(n-9) -344*a(n-10) -176*a(n-11) +64*a(n-12) -64*a(n-13) +128*a(n-14). %e A207600 Some solutions for n=4 %e A207600 ..0..1..1..1....1..0..0..1....1..0..1..1....1..0..1..1....0..1..1..0 %e A207600 ..1..1..1..1....0..1..1..1....0..0..1..1....1..1..1..1....1..1..1..0 %e A207600 ..1..0..1..1....0..1..1..0....0..0..1..1....1..0..1..1....0..1..1..0 %Y A207600 Cf. A207599. %K A207600 nonn %O A207600 1,1 %A A207600 _R. H. Hardin_, Feb 19 2012