A318040 Number of nX3 0..1 arrays with every element unequal to 0, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

1, 2, 8, 21, 86, 377, 1648, 7261, 31969, 140758, 619822, 2729394, 12018832, 52924798, 233054021, 1026252071, 4519095292, 19899811452, 87628711701, 385872557006, 1699187715083, 7482363905416, 32948548958936, 145088757010002

Offset

1,2

Comments

Column 3 of A318045.

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -15*a(n-2) +21*a(n-3) -25*a(n-4) +6*a(n-5) +9*a(n-6) -22*a(n-7) +44*a(n-8) -16*a(n-9) +32*a(n-10) -20*a(n-11) -31*a(n-12) -a(n-13) +2*a(n-14) -2*a(n-15) -18*a(n-16) +3*a(n-17) +12*a(n-18) +14*a(n-19) +3*a(n-20) -2*a(n-21) for n>23

Example

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

Crossrefs

Cf. A318045.

Sequence in context: A219970 A107361 A185309 * A333705 A085077 A272827

Adjacent sequences: A318037 A318038 A318039 * A318041 A318042 A318043

Keyword

nonn

Author

R. H. Hardin, Aug 13 2018

Status

approved