cp's OEIS Frontend

A208711 Number of 4Xn 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.

%I A208711 #7 Jul 22 2025 21:29:19
%S A208711 8,128,1372,16084,185344,2142580,24754628,286034292,3305009328,
%T A208711 38188137788,441249345280,5098468022268,58910854227068,
%U A208711 680692462409636,7865141904908344,90878716312611076,1050068921631026592
%N A208711 Number of 4Xn 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.
%C A208711 Row 4 of A208709
%H A208711 R. H. Hardin, <a href="/A208711/b208711.txt">Table of n, a(n) for n = 1..210</a>
%F A208711 Empirical: a(n) = 9*a(n-1) +31*a(n-2) -11*a(n-3) -71*a(n-4) -a(n-5) +38*a(n-6) -8*a(n-7) for n>9
%e A208711 Some solutions for n=4
%e A208711 ..0..1..0..1....0..1..0..1....0..1..1..0....0..0..0..1....0..0..0..1
%e A208711 ..1..0..1..1....1..1..0..1....0..0..1..0....1..0..1..1....1..0..0..0
%e A208711 ..0..0..0..1....0..1..1..0....0..0..1..1....0..0..1..0....1..1..1..1
%e A208711 ..0..1..0..1....0..0..1..1....1..0..0..0....0..1..0..0....1..0..1..1
%K A208711 nonn
%O A208711 1,1
%A A208711 _R. H. Hardin_ Mar 01 2012