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A180753 Half the number of nX4 binary arrays with each element equal to at least two neighbors 1
0, 2, 2, 9, 21, 70, 207, 658, 2059, 6521, 20602, 65244, 206608, 654594, 2073996, 6571885, 20824917, 65991668, 209121585, 662691890, 2100031249, 6654888151, 21089009696, 66830061534, 211781324846, 671125181554, 2126764718766 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 4 of A180760

LINKS

R. H. Hardin, Table of n, a(n) for n=1..99

FORMULA

Empirical: a(n) = 5*a(n-1) - 6*a(n-2) + a(n-3) + a(n-4) - 9*a(n-5) + 4*a(n-6) + a(n-7) + 28*a(n-8) - 16*a(n-9) - 3*a(n-10) + 2*a(n-11) - 6*a(n-12) + 2*a(n-13) - a(n-14)

CROSSREFS

Sequence in context: A019223 A192302 A128535 * A220971 A308519 A205390

Adjacent sequences: A180750 A180751 A180752 * A180754 A180755 A180756

KEYWORD

nonn

AUTHOR

R. H. Hardin Sep 20 2010

STATUS

approved

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Last modified February 6 23:12 EST 2023. Contains 360111 sequences. (Running on oeis4.)