A220243 - OEIS

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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, 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