A318071 Number of nX4 0..1 arrays with every element unequal to 0, 1, 2 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

8, 20, 41, 73, 149, 372, 861, 2016, 4901, 11698, 27986, 67359, 161518, 387556, 930666, 2233451, 5360842, 12868595, 30887501, 74139733, 177960357, 427157604, 1025312853, 2461074852, 5907342192, 14179472548, 34035173339, 81695041734

Offset

1,1

Comments

Column 4 of A318075.

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

Example

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

Crossrefs

Cf. A318075.

Sequence in context: A272995 A273111 A273175 * A308904 A192753 A373492

Adjacent sequences: A318068 A318069 A318070 * A318072 A318073 A318074

Keyword

nonn

Author

R. H. Hardin, Aug 15 2018

Status

approved