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A281159
Number of nX2 0..1 arrays with no element equal to more than three of its king-move neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
1
0, 0, 5, 18, 85, 346, 1388, 5454, 21171, 81250, 309019, 1166316, 4372916, 16300940, 60456037, 223201490, 820709441, 3006697550, 10978569420, 39965443098, 145083078903, 525337769138, 1897732902967, 6840395954992, 24606162295316
OFFSET
1,3
COMMENTS
Column 2 of A281165.
LINKS
FORMULA
Empirical: a(n) = 9*a(n-1) -24*a(n-2) +15*a(n-3) -18*a(n-4) +75*a(n-5) +55*a(n-6) -54*a(n-7) -102*a(n-8) -184*a(n-9) +36*a(n-10) +168*a(n-11) +136*a(n-12) +48*a(n-13) -96*a(n-14) -64*a(n-15)
EXAMPLE
Some solutions for n=4
..0..0. .0..0. .0..0. .0..0. .0..1. .0..0. .0..1. .0..0. .0..1. .0..1
..1..1. .0..0. .1..1. .0..0. .0..1. .0..0. .1..1. .0..0. .0..0. .0..1
..1..1. .1..0. .1..1. .0..1. .1..1. .1..0. .1..1. .1..0. .0..0. .0..0
..1..1. .0..1. .1..0. .1..1. .1..1. .1..0. .0..0. .1..1. .1..1. .0..0
CROSSREFS
Cf. A281165.
Sequence in context: A343165 A141733 A216723 * A357797 A199257 A188206
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 16 2017
STATUS
approved