A317810 Number of nX3 0..1 arrays with every element unequal to 0, 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

1, 2, 2, 4, 5, 8, 9, 28, 44, 60, 118, 256, 409, 700, 1342, 2570, 4409, 7921, 14776, 27269, 48326, 87891, 161611, 294704, 530298, 966374, 1764843, 3208891, 5812069, 10586099, 19278834, 35040632, 63631413, 115816700, 210701003, 383023861

Offset

1,2

Comments

Column 3 of A317815.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) -a(n-2) +2*a(n-3) +2*a(n-4) -8*a(n-5) +5*a(n-6) -8*a(n-7) +9*a(n-8) -4*a(n-9) +7*a(n-10) +2*a(n-11) -4*a(n-12) -2*a(n-13) -4*a(n-14) +2*a(n-15) -a(n-16) +2*a(n-17) for n>19

Example

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

Crossrefs

Cf. A317815.

Sequence in context: A222707 A326525 A326630 * A308954 A053097 A331443

Adjacent sequences: A317807 A317808 A317809 * A317811 A317812 A317813

Keyword

nonn

Author

R. H. Hardin, Aug 07 2018

Status

approved