A302523 Number of nX3 0..1 arrays with every element equal to 1, 2, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

1, 7, 28, 115, 497, 2086, 9091, 40575, 172996, 760155, 3348129, 14520438, 63606819, 278902951, 1216232548, 5321761651, 23294489377, 101772095142, 445140686771, 1947282645119, 8512898474820, 37229821964539, 162827989419377

Offset

1,2

Comments

Column 3 of A302528.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +7*a(n-2) +34*a(n-3) -44*a(n-4) -182*a(n-5) -a(n-6) +54*a(n-7) +479*a(n-8) -772*a(n-9) +328*a(n-10) +2176*a(n-11) -1456*a(n-12) +1088*a(n-13) -4480*a(n-14) +5120*a(n-15) -2304*a(n-16) -5120*a(n-17) +4096*a(n-18)

Example

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

Crossrefs

Cf. A302528.

Sequence in context: A037597 A037702 A359018 * A290913 A303406 A054626

Adjacent sequences: A302520 A302521 A302522 * A302524 A302525 A302526

Keyword

nonn

Author

R. H. Hardin, Apr 09 2018

Status

approved