A317891 Number of nX3 0..1 arrays with every element unequal to 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

0, 1, 4, 13, 59, 252, 1074, 4633, 19933, 85732, 368847, 1586817, 6826551, 29368380, 126345008, 543545426, 2338372742, 10059853024, 43278232785, 186186164251, 800986675100, 3445904026216, 14824534451888, 63776245668953

Offset

1,3

Comments

Column 3 of A317896.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +8*a(n-3) -10*a(n-4) +3*a(n-5) -17*a(n-6) -7*a(n-7) -21*a(n-8) +6*a(n-9) +10*a(n-10) +4*a(n-11) -18*a(n-12) -21*a(n-13) -9*a(n-14) -a(n-15) +2*a(n-16) for n>18

Example

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

Crossrefs

Cf. A317896.

Sequence in context: A219572 A026663 A149486 * A115455 A241470 A219367

Adjacent sequences: A317888 A317889 A317890 * A317892 A317893 A317894

Keyword

nonn

Author

R. H. Hardin, Aug 10 2018

Status

approved