A297735 - OEIS

%I #4 Jan 04 2018 22:19:25

%S 1,3,17,34,92,223,700,1747,4931,12767,35978,94910,262007,698588,

%T 1916541,5144619,14035991,37816996,102894248,277866327,754687018,

%U 2040711739,5537019209,14984261865,40631762944,110008357730,298195807995

%N Number of 3Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 2 or 4 neighboring 1s.

%C Row 3 of A297733.

%H R. H. Hardin, <a href="/A297735/b297735.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) +7*a(n-4) -12*a(n-5) -19*a(n-6) +16*a(n-7) +10*a(n-8) +4*a(n-9)

%e Some solutions for n=7

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

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

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

%Y Cf. A297733.

%K nonn

%O 1,2

%A _R. H. Hardin_, Jan 04 2018