A304954 Number of nX3 0..1 arrays with every element unequal to 1, 2, 3, 5 or 7 king-move adjacent elements, with upper left element zero.

1, 16, 42, 118, 371, 1203, 3917, 12919, 42060, 137964, 453179, 1485554, 4873627, 15999482, 52491249, 172244821, 565295892, 1855010713, 6087300807, 19976720519, 65555588200, 215127264249, 705970664448, 2316727402348, 7602611158078

Offset

1,2

Comments

Column 3 of A304959.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +4*a(n-2) +8*a(n-3) -12*a(n-4) -42*a(n-5) +3*a(n-6) +a(n-7) +30*a(n-8) +58*a(n-9) +60*a(n-10) +18*a(n-11) -90*a(n-12) -70*a(n-13) -48*a(n-14) +30*a(n-15) +39*a(n-16) +2*a(n-17) +4*a(n-18) -4*a(n-19) -4*a(n-20) for n>21

Example

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

Crossrefs

Cf. A304959.

Sequence in context: A317761 A318340 A318072 * A218067 A187729 A088800

Adjacent sequences: A304951 A304952 A304953 * A304955 A304956 A304957

Keyword

nonn

Author

R. H. Hardin, May 22 2018

Status

approved