A281396 Number of nX4 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

0, 52, 314, 1020, 2886, 7064, 17194, 42396, 101410, 239524, 564328, 1316460, 3049172, 7035996, 16153984, 36917768, 84107390, 191019984, 432482066, 976716232, 2200907846, 4948595320, 11104739122, 24876065280, 55634282916

Offset

1,2

Comments

Column 4 of A281400.

Links

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

Formula

Empirical: a(n) = a(n-1) +2*a(n-2) +8*a(n-3) +a(n-4) -17*a(n-5) -37*a(n-6) -27*a(n-7) +20*a(n-8) +62*a(n-9) +50*a(n-10) -14*a(n-11) -45*a(n-12) -21*a(n-13) +9*a(n-14) +9*a(n-15) for n>21

Example

Some solutions for n=4
..0..0..1..0. .0..1..0..0. .0..1..1..0. .0..0..1..0. .0..1..1..0
..1..0..1..0. .0..1..1..1. .1..0..0..0. .1..0..1..0. .0..0..1..0
..0..0..1..1. .0..1..0..1. .1..0..1..1. .1..0..0..1. .1..1..1..0
..1..0..0..1. .0..1..0..0. .0..0..1..0. .0..0..1..1. .0..0..1..1

Crossrefs

Cf. A281400.

Sequence in context: A118328 A079414 A270769 * A232903 A262757 A262477

Adjacent sequences: A281393 A281394 A281395 * A281397 A281398 A281399

Keyword

nonn

Author

R. H. Hardin, Jan 21 2017

Status

approved