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A240651 Number of nX3 0..1 arrays with no element equal to exactly one horizontal or vertical neighbor, with new values 0..1 introduced in row major order 1
1, 2, 9, 17, 43, 136, 402, 1180, 3518, 10525, 31454, 94059, 281484, 842574, 2522415, 7552239, 22613578, 67714627, 202772197, 607215863, 1818375168, 5445371326, 16306993036, 48833947510, 146241553581, 437945846008, 1311506541151 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A240656

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) +a(n-2) +2*a(n-3) -11*a(n-4) -12*a(n-5) -9*a(n-6) +15*a(n-7) +23*a(n-8) +20*a(n-9) -6*a(n-10) -15*a(n-11) -12*a(n-12) -2*a(n-13) +3*a(n-14) +a(n-15)

EXAMPLE

Some solutions for n=4

..0..0..0....0..1..0....0..0..0....0..0..0....0..0..1....0..0..0....0..0..1

..0..0..0....1..0..1....0..1..0....0..0..0....0..0..0....0..0..0....0..0..0

..0..0..0....0..1..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0

..0..0..0....1..0..1....0..0..1....1..0..0....0..0..1....0..0..1....1..0..0

CROSSREFS

Sequence in context: A100291 A126082 A083707 * A282519 A103256 A028881

Adjacent sequences:  A240648 A240649 A240650 * A240652 A240653 A240654

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 09 2014

STATUS

approved

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Last modified January 27 14:39 EST 2020. Contains 331295 sequences. (Running on oeis4.)