A269105 Number of nX4 0..3 arrays with some element plus some horizontally or vertically adjacent neighbor totalling three no more than once.

216, 15540, 872460, 43964700, 2085484068, 95166487524, 4227147007836, 184069947098892, 7894012975085748, 334480929126425748, 14034341507370527532, 584107408947764887164, 24145251769444080595908

Offset: 1

Author

R. H. Hardin, Feb 19 2016

Keywords

• nonn

Comments

Column 4 of A269109.

Examples

			Some solutions for n=2
..3..2..0..2. .3..1..1..0. .2..3..1..3. .3..0..0..2. .0..0..2..3
..2..0..0..1. .2..0..3..1. .2..2..3..3. .3..1..0..0. .0..0..3..1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Cf. A269109.

Formula

Empirical: a(n) = 90*a(n-1) -2559*a(n-2) +24556*a(n-3) -94959*a(n-4) +140442*a(n-5) -69169*a(n-6) for n>7