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A228478 Number of n X 4 binary arrays with top left value 1 and no two ones adjacent horizontally, vertically or antidiagonally. 1
3, 9, 41, 172, 728, 3084, 13050, 55252, 233875, 990055, 4191028, 17741339, 75101906, 317918500, 1345800258, 5696989354, 24116274286, 102088075950, 432155280235, 1829382955772, 7744072911728, 32781908823977, 138771103836595 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Same recurrences as A228285 except in addition a smaller one for column 5.

LINKS

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

FORMULA

a(n) = a(n-1) + 10*a(n-2) + 15*a(n-3) + 4*a(n-4) - 6*a(n-5) - a(n-6) + 3*a(n-7) - a(n-8).

Empirical g.f.: x*(3 + 6*x + 2*x^2 - 4*x^3 - x^4 + 3*x^5 - x^6) / (1 - x - 10*x^2 - 15*x^3 - 4*x^4 + 6*x^5 + x^6 - 3*x^7 + x^8). - Colin Barker, Sep 11 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 4 of A228482.

Sequence in context: A179088 A027893 A018417 * A320918 A325289 A274739

Adjacent sequences:  A228475 A228476 A228477 * A228479 A228480 A228481

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 22 2013

STATUS

approved

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Last modified September 18 07:50 EDT 2019. Contains 327168 sequences. (Running on oeis4.)