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 A207876 #7 Jul 22 2025 20:54:42 %S A207876 13,169,336,824,1648,4160,8892,19710,44868,100056,224792,497348, %T A207876 1123364,2520128,5603808,12569064,28201200,63082040,140941364, %U A207876 315874560,707891088,1582568420,3541951148,7935579276,17763012916,39742042856 %N A207876 Number of nX5 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 0 and 1 1 1 vertically. %C A207876 Column 5 of A207879 %H A207876 R. H. Hardin, <a href="/A207876/b207876.txt">Table of n, a(n) for n = 1..210</a> %F A207876 Empirical: a(n) = a(n-2) +8*a(n-3) +7*a(n-4) -28*a(n-6) -4*a(n-7) +19*a(n-8) +36*a(n-9) -24*a(n-10) -18*a(n-11) -6*a(n-12) +10*a(n-14) for n>20 %e A207876 Some solutions for n=4 %e A207876 ..1..0..0..1..0....1..0..0..1..0....0..1..0..0..1....1..0..0..1..1 %e A207876 ..1..1..0..0..1....0..1..1..1..0....1..0..0..1..0....0..0..1..0..0 %e A207876 ..0..1..0..0..1....1..1..1..0..0....1..0..0..1..0....1..1..1..0..0 %e A207876 ..1..0..0..1..0....1..0..0..1..0....0..1..1..0..0....1..1..0..0..1 %K A207876 nonn %O A207876 1,1 %A A207876 _R. H. Hardin_ Feb 21 2012