A301486 Number of nX3 0..1 arrays with every element equal to 0, 1, 2, 4, 5 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

4, 18, 52, 148, 441, 1372, 4326, 13641, 42741, 133208, 414303, 1289070, 4015530, 12519594, 39044533, 121754095, 379591807, 1183290025, 3688511653, 11498007929, 35843459506, 111739411177, 348340800464, 1085925223300, 3385266114712

Offset

1,1

Comments

Column 3 of A301491.

Links

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

Formula

Empirical: a(n) = 8*a(n-1) -22*a(n-2) +15*a(n-3) +44*a(n-4) -86*a(n-5) +a(n-6) +87*a(n-7) -13*a(n-8) -39*a(n-9) +19*a(n-10) -56*a(n-11) -26*a(n-12) +38*a(n-13) +90*a(n-14) +118*a(n-15) -46*a(n-16) -18*a(n-17) -120*a(n-18) -6*a(n-19) -15*a(n-20) +26*a(n-21) +3*a(n-23) -a(n-24) for n>25

Example

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

Crossrefs

Cf. A301491.

Sequence in context: A059133 A300493 A300876 * A284607 A297945 A320544

Adjacent sequences: A301483 A301484 A301485 * A301487 A301488 A301489

Keyword

nonn

Author

R. H. Hardin, Mar 22 2018

Status

approved