cp's OEIS Frontend

A209221 Number of nX5 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 1 0 and 1 1 1 vertically.

%I A209221 #7 Jul 22 2025 21:40:56
%S A209221 15,225,240,504,900,1776,3456,6300,12656,24124,45276,88400,170280,
%T A209221 323760,618496,1202400,2300200,4360824,8464860,16284576,30897024,
%U A209221 59537156,115023968,219164204,419459908,811024296,1553149080,2962595040
%N A209221 Number of nX5 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 1 0 and 1 1 1 vertically.
%C A209221 Column 5 of A209224
%H A209221 R. H. Hardin, <a href="/A209221/b209221.txt">Table of n, a(n) for n = 1..210</a>
%F A209221 Empirical: a(n) = 9*a(n-3) +2*a(n-4) -33*a(n-6) +10*a(n-7) +3*a(n-8) +66*a(n-9) -33*a(n-10) +5*a(n-11) -83*a(n-12) +39*a(n-13) -20*a(n-14) +78*a(n-15) +3*a(n-16) -7*a(n-17) -45*a(n-18) -30*a(n-19) +8*a(n-20) +22*a(n-21) +10*a(n-22) +2*a(n-23) -6*a(n-24) +a(n-25) +a(n-27) for n>29
%e A209221 Some solutions for n=4
%e A209221 ..1..1..1..0..1....1..1..0..1..1....1..1..1..1..1....0..0..1..1..0
%e A209221 ..0..0..1..1..0....1..1..0..0..1....1..1..0..0..1....1..1..0..1..1
%e A209221 ..1..0..0..1..1....0..0..1..1..0....0..0..1..1..0....1..1..1..0..1
%e A209221 ..1..1..1..0..1....1..1..1..1..0....0..0..1..1..1....0..0..1..1..0
%K A209221 nonn
%O A209221 1,1
%A A209221 _R. H. Hardin_ Mar 06 2012