A280805 Number of nX3 0..1 arrays with no element equal to more than two of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

0, 3, 56, 332, 1578, 6540, 24490, 86010, 288426, 933792, 2940425, 9053479, 27364145, 81436340, 239191322, 694661663, 1997809427, 5696648777, 16121608346, 45319683250, 126637762818, 351964959409, 973463999825, 2680515593254

Offset

1,2

Comments

Column 3 of A280810.

Links

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

Formula

Empirical: a(n) = 12*a(n-1) -57*a(n-2) +127*a(n-3) -93*a(n-4) -129*a(n-5) +216*a(n-6) +165*a(n-7) -477*a(n-8) +66*a(n-9) +411*a(n-10) -123*a(n-11) -319*a(n-12) +183*a(n-13) +102*a(n-14) -81*a(n-15) -30*a(n-16) +36*a(n-17) -8*a(n-18) for n>24

Example

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

Crossrefs

Cf. A280810.

Sequence in context: A119188 A111451 A285450 * A198184 A262398 A263886

Adjacent sequences: A280802 A280803 A280804 * A280806 A280807 A280808

Keyword

nonn

Author

R. H. Hardin, Jan 08 2017

Status

approved