A301526 Number of nX3 0..1 arrays with every element equal to 0, 2, 3, 4, 5 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

1, 5, 24, 92, 391, 1728, 7640, 33824, 150119, 667154, 2966513, 13194447, 58695455, 261128908, 1161781427, 5168968740, 22997926659, 102323706303, 455266100243, 2025606769591, 9012502023966, 40099210902427, 178412956961941

Offset

1,2

Comments

Column 3 of A301531.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +9*a(n-2) -3*a(n-3) -26*a(n-4) -39*a(n-5) -45*a(n-6) -20*a(n-7) +31*a(n-8) +40*a(n-9) -10*a(n-10) -34*a(n-11) +2*a(n-12) +32*a(n-13) +20*a(n-14) +14*a(n-15) +a(n-16) -3*a(n-17) -2*a(n-18) -a(n-20) for n>21

Example

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

Crossrefs

Cf. A301531.

Sequence in context: A145914 A066316 A271458 * A180354 A212349 A268370

Adjacent sequences: A301523 A301524 A301525 * A301527 A301528 A301529

Keyword

nonn

Author

R. H. Hardin, Mar 23 2018

Status

approved