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A240514 Number of nX3 0..1 arrays with no element equal to exactly two horizontal and vertical neighbors, with new values 0..1 introduced in row major order 1
3, 6, 10, 28, 73, 196, 515, 1376, 3686, 9914, 26681, 71876, 193749, 522510, 1409414, 3802164, 10257707, 27675148, 74669353, 201466240, 543583450, 1466670482, 3957312647, 10677488468, 28809678971, 77733469590, 209738364682 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A240519

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) -3*a(n-2) -2*a(n-3) +2*a(n-4) +2*a(n-5) -7*a(n-6) -8*a(n-7) +15*a(n-8) +4*a(n-9) -8*a(n-10) -4*a(n-11) +15*a(n-12) +8*a(n-13) -7*a(n-14) -2*a(n-15) +2*a(n-16) +2*a(n-17) -3*a(n-18) -4*a(n-19) -a(n-20)

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Sequence in context: A068866 A110891 A197435 * A115887 A068195 A080506

Adjacent sequences:  A240511 A240512 A240513 * A240515 A240516 A240517

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 06 2014

STATUS

approved

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Last modified November 13 04:20 EST 2019. Contains 329085 sequences. (Running on oeis4.)