A305644 Number of n X 3 0..1 arrays with every element unequal to 0, 1, 3, 4, 5 or 6 king-move adjacent elements, with upper left element zero.

3, 9, 13, 31, 79, 168, 430, 1241, 3577, 10976, 35220, 115104, 382846, 1287463, 4355297, 14794917, 50378019, 171779607, 586281739, 2002004862, 6838403076, 23363178277, 79828543393, 272780054792, 932149927652, 3185441895514

Offset

1,1

Comments

Column 3 of A305649.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) -7*a(n-2) +17*a(n-3) -52*a(n-4) +50*a(n-5) -48*a(n-6) +92*a(n-7) -45*a(n-8) -17*a(n-9) +68*a(n-10) -44*a(n-11) -5*a(n-12) -127*a(n-13) +174*a(n-14) -54*a(n-15) -16*a(n-16) +8*a(n-17) for n>19

Example

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

Crossrefs

Cf. A305649.

Sequence in context: A215443 A304664 A068885 * A316920 A018292 A089147

Adjacent sequences: A305641 A305642 A305643 * A305645 A305646 A305647

Keyword

nonn

Author

R. H. Hardin, Jun 07 2018

Status

approved