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A218843 Unmatched value maps: number of 2 X n binary arrays indicating the locations of corresponding elements not equal to any horizontal or antidiagonal neighbor in a random 0..1 2 X n array. 1
1, 7, 20, 57, 156, 438, 1220, 3398, 9468, 26380, 73496, 204780, 570556, 1589672, 4429140, 12340436, 34382820, 95797176, 266909376, 743660900, 2071982512, 5772942284, 16084528900, 44814595084, 124862092120, 347889834096 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 2 of A218842.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) + a(n-2) + 3*a(n-3) + 2*a(n-5) + 2*a(n-6) - 2*a(n-7) for n>9.

Empirical g.f.: x*(1 + 5*x + 5*x^2 + 7*x^3 + x^4 + 7*x^5 + x^6 - 2*x^8) / (1 - 2*x - x^2 - 3*x^3 - 2*x^5 - 2*x^6 + 2*x^7). - Colin Barker, Jul 24 2018

EXAMPLE

Some solutions for n=3:

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

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

CROSSREFS

Cf. A218842.

Sequence in context: A320681 A048755 A055267 * A219422 A209546 A222549

Adjacent sequences:  A218840 A218841 A218842 * A218844 A218845 A218846

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 07 2012

STATUS

approved

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Last modified December 1 16:44 EST 2021. Contains 349430 sequences. (Running on oeis4.)