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A233785 Number of (n+1) X (1+1) 0..3 arrays with every 2 X 2 subblock having the sum of the squares of all six edge and diagonal differences equal to 11. 1
48, 188, 720, 2856, 11040, 43888, 169920, 675744, 2616960, 10407872, 40308480, 160311936, 620874240, 2469299968, 9563397120, 38034921984, 147306178560, 585856596992, 2268975329280, 9024021866496, 34949308784640, 138998129717248 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 18*a(n-2) - 40*a(n-4).

Empirical g.f.: 4*x*(12 + 47*x - 36*x^2 - 132*x^3) / (1 - 18*x^2 + 40*x^4). - Colin Barker, Oct 11 2018

EXAMPLE

Some solutions for n=5:

..2..1....1..2....3..1....2..1....1..2....1..3....0..2....3..2....0..0....2..0

..0..2....2..0....3..2....2..0....0..0....2..1....1..2....1..1....2..1....2..1

..2..1....1..2....3..1....2..1....2..1....1..3....1..3....3..2....3..1....0..0

..1..3....2..0....2..1....3..3....3..1....2..3....2..1....1..3....1..2....2..1

..1..2....1..0....2..0....2..1....2..1....3..1....1..3....1..2....2..0....2..0

..0..2....2..0....1..2....2..0....3..1....2..1....3..2....2..0....1..2....1..2

CROSSREFS

Column 1 of A233792.

Sequence in context: A130566 A233792 A233967 * A233960 A210250 A259038

Adjacent sequences:  A233782 A233783 A233784 * A233786 A233787 A233788

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 15 2013

STATUS

approved

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Last modified September 19 12:43 EDT 2020. Contains 337178 sequences. (Running on oeis4.)