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A230937 Number of white-square subarrays of (n+2) X (3+2) 0..3 arrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, no adjacent elements equal, and upper left element zero. 1
2, 16, 34, 232, 522, 3768, 8450, 60824, 136474, 982552, 2204498, 15870936, 35608874, 256361112, 575185186, 4140964568, 9290884794, 66888415128, 150074347890, 1080439106264, 2424129709770, 17452180031640, 39156624254530 (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) = 16*a(n-2) +3*a(n-4) -10*a(n-6) +24*a(n-8) -16*a(n-10).

Empirical g.f.: 2*x*(1 + 8*x + x^2 - 12*x^3 - 14*x^4 + 4*x^5 + 8*x^6) / (1 - 16*x^2 - 3*x^4 + 10*x^6 - 24*x^8 + 16*x^10). - Colin Barker, Sep 23 2018

EXAMPLE

Some solutions for n=4:

..0..x..0..x..0....0..x..2..x..2....0..x..2..x..2....0..x..2..x..2

..x..1..x..1..x....x..1..x..3..x....x..1..x..3..x....x..1..x..3..x

..0..x..2..x..0....2..x..0..x..2....0..x..0..x..2....0..x..0..x..0

..x..1..x..3..x....x..3..x..1..x....x..3..x..3..x....x..3..x..1..x

..0..x..2..x..2....2..x..0..x..0....2..x..2..x..2....0..x..2..x..0

..x..1..x..1..x....x..1..x..3..x....x..1..x..1..x....x..1..x..3..x

CROSSREFS

Column 3 of A230940.

Sequence in context: A012392 A009819 A189332 * A018951 A019064 A123135

Adjacent sequences:  A230934 A230935 A230936 * A230938 A230939 A230940

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 01 2013

STATUS

approved

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Last modified August 17 08:02 EDT 2022. Contains 356184 sequences. (Running on oeis4.)