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A220243 Equals two maps: number of nX2 binary arrays indicating the locations of corresponding elements equal to exactly two of their king-move neighbors in a random 0..1 nX2 array 1
1, 5, 18, 37, 85, 184, 393, 826, 1726, 3568, 7342, 15009, 30562, 62034, 125493, 253311, 510438, 1026775, 2063029, 4141268, 8305979, 16649028, 33356608, 66803160, 133746856, 267712961, 535761706, 1072043156, 2144889675, 4291005857 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A220247

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) -a(n-2) +3*a(n-3) -14*a(n-4) +2*a(n-5) +3*a(n-6) +21*a(n-7) +6*a(n-8) -16*a(n-9) -12*a(n-10) -16*a(n-11) +12*a(n-12) +4*a(n-13) +8*a(n-14) for n>16

EXAMPLE

Some solutions for n=3

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

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

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

CROSSREFS

Sequence in context: A031051 A294090 A038346 * A065007 A031428 A007742

Adjacent sequences:  A220240 A220241 A220242 * A220244 A220245 A220246

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 08 2012

STATUS

approved

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Last modified April 10 20:35 EDT 2021. Contains 342856 sequences. (Running on oeis4.)