A303685 Number of nX3 0..1 arrays with every element unequal to 2, 3 or 4 king-move adjacent elements, with upper left element zero.

0, 5, 2, 20, 27, 108, 191, 599, 1261, 3503, 8019, 20956, 49932, 126833, 308197, 772321, 1894368, 4716189, 11620491, 28839210, 71214717, 176468284, 436228102, 1080165740, 2671530008, 6612751510, 16359100711, 40486188269, 100169626090

Offset

1,2

Comments

Column 3 of A303690.

Links

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

Formula

Empirical: a(n) = a(n-1) +6*a(n-2) -3*a(n-3) -9*a(n-4) +7*a(n-5) +3*a(n-6) -20*a(n-7) -3*a(n-8) +12*a(n-9) -12*a(n-11) -3*a(n-12) +2*a(n-13) -5*a(n-14) +a(n-15) +2*a(n-16) for n>18

Example

Some solutions for n=5
..0..1..0. .0..1..0. .0..1..1. .0..1..0. .0..1..0. .0..0..1. .0..1..0
..1..0..1. .1..1..1. .1..0..0. .1..0..1. .1..1..1. .1..1..0. .1..0..1
..1..0..0. .0..1..0. .0..0..1. .0..1..0. .0..1..0. .0..1..1. .0..0..1
..0..0..1. .0..0..1. .1..0..1. .1..1..1. .1..0..0. .0..1..0. .1..0..0
..1..0..1. .1..1..0. .0..1..0. .0..1..0. .1..0..1. .1..0..1. .1..0..1

Crossrefs

Cf. A303690.

Sequence in context: A327316 A206582 A276533 * A189746 A191667 A130329

Adjacent sequences: A303682 A303683 A303684 * A303686 A303687 A303688

Keyword

nonn

Author

R. H. Hardin, Apr 28 2018

Status

approved