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A228656 Number of nX4 binary arrays with top left value 1 and no two ones adjacent horizontally, diagonally or antidiagonally. 1
3, 14, 78, 416, 2228, 11912, 63688, 340480, 1820208, 9730784, 52020448, 278099456, 1486709568, 7947894912, 42489154688, 227145461760, 1214311301888, 6491663650304, 34704195603968, 185527355908096, 991822435038208 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A228660

LINKS

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

FORMULA

Empirical: a(n) = 6*a(n-1) -2*a(n-2) -8*a(n-3).

Empirical: G.f. -x*(-3+4*x) / ( 1-6*x+2*x^2+8*x^3 ). - R. J. Mathar, Aug 29 2013

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Sequence in context: A048779 A052186 A330518 * A244507 A074538 A242426

Adjacent sequences:  A228653 A228654 A228655 * A228657 A228658 A228659

KEYWORD

nonn

AUTHOR

R. H. Hardin Aug 29 2013

STATUS

approved

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Last modified January 24 01:05 EST 2020. Contains 331178 sequences. (Running on oeis4.)