A304217 Number of nX4 0..1 arrays with every element unequal to 0, 1, 3 or 8 king-move adjacent elements, with upper left element zero.

5, 17, 17, 32, 62, 108, 190, 348, 636, 1152, 2082, 3768, 6840, 12412, 22486, 40744, 73872, 133932, 242782, 440076, 797732, 1446128, 2621506, 4752084, 8614284, 15615592, 28307242, 51313936, 93019232, 168620580, 305667118, 554098192

Offset

1,1

Comments

Column 4 of A304221.

Links

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

Formula

Empirical: a(n) = a(n-1) +2*a(n-3) +a(n-4) +a(n-5) -2*a(n-7) for n>9

Example

Some solutions for n=7
..0..0..0..1. .0..1..1..1. .0..1..1..0. .0..0..0..0. .0..0..0..1
..0..0..1..1. .1..1..1..1. .1..1..1..1. .0..0..0..0. .0..0..0..0
..0..1..1..1. .1..1..1..1. .1..1..1..1. .0..0..0..0. .0..0..0..0
..1..1..1..1. .1..1..0..1. .1..1..1..0. .0..1..0..0. .0..0..0..0
..1..1..1..1. .1..1..1..1. .1..1..0..0. .0..0..0..0. .0..0..0..0
..1..1..1..1. .1..1..1..1. .1..0..0..0. .0..0..0..0. .0..0..0..1
..0..1..1..0. .0..1..1..1. .0..0..0..0. .0..0..0..0. .0..0..1..1

Crossrefs

Cf. A304221.

Sequence in context: A237437 A128895 A141558 * A305248 A231710 A316548

Adjacent sequences: A304214 A304215 A304216 * A304218 A304219 A304220

Keyword

nonn

Author

R. H. Hardin, May 08 2018

Status

approved