A304349 Number of nX2 0..1 arrays with every element unequal to 0, 1, 3, 4 or 5 king-move adjacent elements, with upper left element zero.

2, 5, 9, 21, 57, 125, 289, 741, 1737, 4045, 9969, 23861, 56217, 135965, 326849, 776581, 1864297, 4479085, 10691729, 25606101, 61438777, 146972605, 351821409, 843331621, 2019112457, 4833683725, 11580336689, 27733236341, 66402706137

Offset

1,1

Comments

Column 2 of A304355.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) -a(n-2) +8*a(n-3) -8*a(n-4)

Example

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

Crossrefs

Cf. A304355.

Sequence in context: A001851 A356375 A303963 * A024822 A218966 A029726

Adjacent sequences: A304346 A304347 A304348 * A304350 A304351 A304352

Keyword

nonn

Author

R. H. Hardin, May 11 2018

Status

approved