A280854 Number of n X 3 0..2 arrays with no element equal to more than one of its king-move neighbors and with new values introduced in order 0 sequentially upwards.

4, 29, 46, 96, 256, 678, 1698, 4358, 11218, 28650, 73354, 188066, 481554, 1233194, 3159018, 8091050, 20722730, 53077762, 135947682, 348198514, 891836994, 2284251018, 5850611770, 14985083066, 38381073050, 98304843826, 251786685106

Offset: 1

Author

R. H. Hardin, Jan 09 2017

Keywords

• nonn

Examples

			Some solutions for n=4:
..0..0..1. .0..1..1. .0..0..1. .0..1..0. .0..1..2. .0..1..0. .0..0..1
..1..2..1. .0..2..2. .1..2..2. .2..2..1. .2..1..0. .2..1..2. .2..1..2
..0..2..0. .1..1..0. .0..1..0. .1..0..0. .2..0..2. .2..0..2. .2..0..0
..1..1..0. .0..2..2. .0..2..2. .1..2..2. .1..1..2. .1..1..0. .1..1..2
		

Links

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

Crossrefs

Column 3 of A280859.

Formula

Empirical: a(n) = 2*a(n-1) + 4*a(n-3) - a(n-4) + 2*a(n-6) - 2*a(n-7) for n>9.

Empirical g.f.: x*(4 + 21*x - 12*x^2 - 12*x^3 - 48*x^4 + 11*x^5 - 4*x^6 - 16*x^7 + 12*x^8) / (1 - 2*x - 4*x^3 + x^4 - 2*x^6 + 2*x^7). - Colin Barker, Feb 14 2019