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A222684 Number of nX2 0..2 arrays with exactly floor(nX2/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..2 order 1
0, 3, 8, 50, 216, 1120, 5440, 27576, 138560, 704880, 3590400, 18382208, 94348800, 485706240, 2505943040, 12956458880, 67108497408, 348156924160, 1808830924800, 9409953735168, 49010429163520, 255537995550720, 1333668320575488 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A222690

LINKS

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

FORMULA

From Vaclav Kotesovec, May 23 2013: (Start)

Empirical: 3*(n-1)*n*(49*n-73)*a(n) = 5*(n-1)*(98*n^2-195*n+91)*a(n-1) + 5*(7*n-5)*(49*n^2-136*n+96)*a(n-2) - 8*(n-1)*(2*n-5)*(49*n-24)*a(n-3)

a(n) ~ 16^n/(3^n*sqrt(21*Pi*n)). (End)

EXAMPLE

All solutions for n=3

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

..1..2....0..0....1..0....0..0....0..1....2..2....0..1....0..0

..2..2....1..2....0..0....1..0....0..0....2..2....2..2....0..0

CROSSREFS

Sequence in context: A194364 A338439 A005444 * A208801 A019044 A265961

Adjacent sequences:  A222681 A222682 A222683 * A222685 A222686 A222687

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 28 2013

STATUS

approved

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Last modified October 23 03:42 EDT 2021. Contains 348211 sequences. (Running on oeis4.)