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Number of 2Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 0, 2 or 4 neighboring 1s.
1

%I #4 Jan 03 2018 12:29:02

%S 4,8,26,60,176,436,1216,3120,8488,22160,59552,156816,418880,1107712,

%T 2950048,7817664,20789248,55148864,146548736,388957440,1033216640,

%U 2742970624,7285063168,19342708992,51367846912,136396150784,362207435264

%N Number of 2Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 0, 2 or 4 neighboring 1s.

%C Row 2 of A297694.

%H R. H. Hardin, <a href="/A297695/b297695.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) +4*a(n-2) -6*a(n-3)

%e Some solutions for n=7

%e ..1..0..0..0..0..1..0. .1..0..1..0..0..0..0. .1..0..0..1..0..1..1

%e ..1..0..1..0..0..1..0. .1..0..0..0..1..0..0. .1..0..1..1..1..1..0

%Y Cf. A297694.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 03 2018