A228657 - OEIS

A228657

Number of n X 5 binary arrays with top left value 1 and no two ones adjacent horizontally, diagonally or antidiagonally.

5, 38, 335, 2844, 24109, 203762, 1720343, 14516920, 122469941, 1033083774, 8714026943, 73500740436, 619954240797, 5229079954762, 44105207907655, 372009451809136, 3137746452123621, 26465592072488918, 223226285220003247

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OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 12*a(n-1) - 27*a(n-2) - 32*a(n-3) + 49*a(n-4) + 20*a(n-5) - 5*a(n-6).

Empirical g.f.: x*(5 - 22*x + 14*x^2 + 10*x^3 - 3*x^4) / (1 - 12*x + 27*x^2 + 32*x^3 - 49*x^4 - 20*x^5 + 5*x^6). - Colin Barker, Sep 12 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 5 of A228660.

Sequence in context: A247773 A207411 A316598 * A370476 A369480 A365839

Adjacent sequences: A228654 A228655 A228656 * A228658 A228659 A228660

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 29 2013

STATUS

approved