A305913 Number of nX3 0..1 arrays with every element unequal to 0, 1, 3, 4, 5 or 7 king-move adjacent elements, with upper left element zero.

3, 9, 13, 27, 62, 135, 312, 825, 2367, 6940, 21330, 67814, 216690, 699884, 2279373, 7427118, 24244543, 79292187, 259332414, 848386032, 2776599349, 9087224618, 29741257114, 97348224464, 318637326698, 1042951906150, 3413821643656

Offset

1,1

Comments

Column 3 of A305918.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +a(n-2) +7*a(n-3) -19*a(n-4) -21*a(n-5) +18*a(n-6) -23*a(n-7) +17*a(n-8) +55*a(n-9) +83*a(n-10) -23*a(n-11) -120*a(n-12) -20*a(n-13) +78*a(n-14) +9*a(n-15) -22*a(n-16) +2*a(n-18) for n>20

Example

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

Crossrefs

Cf. A305918.

Sequence in context: A014861 A018407 A304350 * A215443 A304664 A068885

Adjacent sequences: A305910 A305911 A305912 * A305914 A305915 A305916

Keyword

nonn

Author

R. H. Hardin, Jun 14 2018

Status

approved