A281564 Number of 2Xn 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

0, 0, 5, 18, 141, 602, 2180, 7006, 20979, 59698, 163635, 435900, 1135036, 2901852, 7307093, 18167506, 44683929, 108886702, 263208036, 631773802, 1507041943, 3575151970, 8439694735, 19835439712, 46433224508, 108305733064, 251797970649

Offset

1,3

Comments

Row 2 of A281563.

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -10*a(n-2) -29*a(n-3) +68*a(n-4) +67*a(n-5) -195*a(n-6) -108*a(n-7) +306*a(n-8) +132*a(n-9) -276*a(n-10) -96*a(n-11) +136*a(n-12) +32*a(n-13) -32*a(n-14) for n>15

Example

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

Crossrefs

Cf. A281563.

Sequence in context: A140296 A278172 A204252 * A291356 A091059 A352663

Adjacent sequences: A281561 A281562 A281563 * A281565 A281566 A281567

Keyword

nonn

Author

R. H. Hardin, Jan 24 2017

Status

approved