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Number of 3 X 3Xnn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 0 or 2 neighboring 1s.
Row 3 of A297457.
Empirical: a(n) = 3*a(n-1) +) + 4*a(n-2) -) - 7*a(n-3) +) + 8*a(n-4) -) - 19*a(n-5) +) + 8*a(n-6) +) + 2*a(n-8)).
Empirical g.f.: x*(8 - 5*x + 3*x^2 - 11*x^3 - 11*x^4 + 8*x^5 + 2*x^6 + 2*x^7) / (1 - 3*x - 4*x^2 + 7*x^3 - 8*x^4 + 19*x^5 - 8*x^6 - 2*x^8). - Colin Barker, Feb 28 2019
Some solutions for n=7:
Cf. Row 3 of A297457.
R. H. Hardin, <a href="/A297459/b297459.txt">Table of n, a(n) for n = 1..210</a>
allocated for R. H. Hardin
Number of 3Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 0 or 2 neighboring 1s.
8, 19, 92, 285, 1143, 3933, 14817, 52868, 194822, 704284, 2575201, 9352440, 34103042, 124055943, 451921339, 1644897204, 5990104595, 21807171062, 79403933671, 289093577711, 1052597637063, 3832392357045, 13953632474038
1,1
Empirical: a(n) = 3*a(n-1) +4*a(n-2) -7*a(n-3) +8*a(n-4) -19*a(n-5) +8*a(n-6) +2*a(n-8)
Some solutions for n=7
..0..0..1..0..1..1..1. .0..0..1..0..1..0..1. .0..0..0..0..0..0..0
..1..0..0..0..0..1..0. .1..0..0..0..1..0..1. .0..0..0..0..1..0..1
..1..0..1..0..0..1..0. .0..0..0..0..0..0..0. .1..0..1..0..0..0..1
Cf. A297457.
allocated
nonn
R. H. Hardin, Dec 30 2017
