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A221589 Equals one maps: number of n X 4 binary arrays indicating the locations of corresponding elements equal to exactly one of their king-move neighbors in a random 0..3 n X 4 array. 1
8, 180, 3760, 64324, 1043774, 16758008, 268358624, 4294659968, 68718247424, 1099506710528, 17592166375424, 281474898034688, 4503599312666624, 72057592779112448, 1152921499571585024, 18446744053568503808 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A221590.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..92

FORMULA

Empirical: a(n) = 20*a(n-1) -64*a(n-2) for n>6.

Conjectures from Colin Barker, Aug 09 2018: (Start)

G.f.: 2*x*(4 + 10*x + 336*x^2 + 322*x^3 - 1033*x^4 - 368*x^5) / ((1 - 4*x)*(1 - 16*x)).

a(n) = 16^n - 2401*2^(2*n-9) for n>4.

(End)

EXAMPLE

Some solutions for n=3.

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

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

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

CROSSREFS

Cf. A221590.

Sequence in context: A299662 A300255 A108552 * A317486 A060593 A130775

Adjacent sequences:  A221586 A221587 A221588 * A221590 A221591 A221592

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 20 2013

STATUS

approved

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Last modified September 15 02:19 EDT 2019. Contains 327062 sequences. (Running on oeis4.)