A304671 Number of nX3 0..1 arrays with every element unequal to 0, 2, 3, 5 or 6 king-move adjacent elements, with upper left element zero.

1, 7, 13, 23, 45, 131, 337, 883, 2389, 6599, 18393, 51475, 144777, 408787, 1156245, 3275327, 9287881, 26355499, 74822993, 212488499, 603573125, 1714703255, 4871817065, 13842752035, 39334524393, 111773515363, 317623880677

Offset

1,2

Comments

Column 3 of A304676.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -8*a(n-3) -13*a(n-4) +20*a(n-5) +21*a(n-6) +4*a(n-7) -30*a(n-8) -44*a(n-9) -17*a(n-10) +72*a(n-11) +116*a(n-12) -20*a(n-13) -72*a(n-14) -52*a(n-15) -12*a(n-16) +24*a(n-17) +8*a(n-18) for n>19

Example

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

Crossrefs

Cf. A304676.

Sequence in context: A227786 A339148 A270792 * A075642 A316118 A265766

Adjacent sequences: A304668 A304669 A304670 * A304672 A304673 A304674

Keyword

nonn

Author

R. H. Hardin, May 16 2018

Status

approved