A304692 Number of nX3 0..1 arrays with every element unequal to 1, 2, 3, 5 or 6 king-move adjacent elements, with upper left element zero.

1, 16, 56, 178, 669, 2615, 9573, 35581, 133149, 495719, 1845526, 6880247, 25634622, 95503501, 355868278, 1325975629, 4940513437, 18408548266, 68590644744, 255569164599, 952255335447, 3548119872982, 13220347086909, 49259228193957

Offset

1,2

Comments

Column 3 of A304697.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +4*a(n-2) +7*a(n-3) -28*a(n-4) -63*a(n-5) -22*a(n-6) +66*a(n-7) +200*a(n-8) +120*a(n-9) -46*a(n-10) -245*a(n-11) -185*a(n-12) -23*a(n-13) +95*a(n-14) +162*a(n-15) +71*a(n-16) -2*a(n-17) -20*a(n-18) -8*a(n-19) for n>21

Example

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

Crossrefs

Cf. A304697.

Sequence in context: A331766 A231971 A333279 * A295986 A169882 A202993

Adjacent sequences: A304689 A304690 A304691 * A304693 A304694 A304695

Keyword

nonn

Author

R. H. Hardin, May 17 2018

Status

approved