A206181 - OEIS

A206181

Number of (n+1) X (n+1) 0..3 arrays with every 2 X 2 subblock having the same number of clockwise edge increases as its horizontal neighbors and the same number of counterclockwise edge increases as its vertical neighbors.

256, 19688, 3802676, 5674969344, 51975660472496, 2363371012699739212

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OFFSET

1,1

COMMENTS

Diagonal of A206188.

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Sequence in context: A206319 A216397 A090650 * A251968 A017116 A206055

Adjacent sequences: A206178 A206179 A206180 * A206182 A206183 A206184

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 04 2012

STATUS

approved