A316920 Number of nX3 0..1 arrays with every element unequal to 0, 1, 3, 4, 5, 6 or 7 king-move adjacent elements, with upper left element zero.

3, 9, 13, 31, 81, 184, 492, 1457, 4371, 13738, 44698, 147992, 497182, 1687343, 5760403, 19745581, 67869355, 233664175, 805343315, 2777680268, 9584619952, 33081967287, 114206172731, 394310805436, 1361508413616, 4701358974926

Offset

1,1

Comments

Column 3 of A316925.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) -6*a(n-2) +14*a(n-3) -52*a(n-4) +39*a(n-5) -20*a(n-6) +84*a(n-7) -17*a(n-8) -6*a(n-9) -7*a(n-10) -50*a(n-11) -16*a(n-12) -47*a(n-13) +144*a(n-14) -64*a(n-15) -12*a(n-16) +8*a(n-17) for n>19

Example

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

Crossrefs

Cf. A316925.

Sequence in context: A304664 A068885 A305644 * A018292 A089147 A094043

Adjacent sequences: A316917 A316918 A316919 * A316921 A316922 A316923

Keyword

nonn

Author

R. H. Hardin, Jul 16 2018

Status

approved