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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.
1
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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 08 2017
STATUS
approved