A228502 - OEIS

A228502

Number of n X 4 binary arrays with top left value 1 and no two ones adjacent horizontally, vertically, diagonally or antidiagonally.

3, 5, 29, 87, 358, 1252, 4749, 17285, 64235, 236211, 873250, 3219652, 11886927, 43856285, 161862005, 597285195, 2204231074, 8134165648, 30017792409, 110774426621, 408792375587, 1508567655759, 5567079710158, 20544224979592

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OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) + 7*a(n-2) - 2*a(n-3) - 3*a(n-4).

Empirical g.f.: x*(1 - x)*(3 + 2*x) / (1 - 2*x - 7*x^2 + 2*x^3 + 3*x^4). - Colin Barker, Sep 12 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..1..0

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

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

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

CROSSREFS

Column 4 of A228506.

Sequence in context: A128551 A154942 A240110 * A215663 A092330 A176951

Adjacent sequences: A228499 A228500 A228501 * A228503 A228504 A228505

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 23 2013

STATUS

approved