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A206662 Number of (n+1) X 3 0..2 arrays with every 2 X 2 subblock having the number of clockwise edge increases equal to the number of counterclockwise edge increases in its adjacent leftward and upward neighbors. 1
423, 2691, 17844, 119727, 815847, 5593611, 38594841, 267189276, 1854776850, 12896494731, 89778289281, 625461045417, 4359732229497, 30399727224177, 212022747357321, 1478983212563424, 10317870774963420, 71985922839937911 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A206668.

LINKS

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

FORMULA

Empirical: a(n) = 14*a(n-1) -37*a(n-2) -242*a(n-3) +1172*a(n-4) +717*a(n-5) -9633*a(n-6) +5674*a(n-7) +31176*a(n-8) -35091*a(n-9) -39354*a(n-10) +60926*a(n-11) +15852*a(n-12) -33558*a(n-13) -12834*a(n-14) +15013*a(n-15) +2888*a(n-16) -2402*a(n-17) -318*a(n-18) -11*a(n-19) +49*a(n-20) for n>22.

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Sequence in context: A203099 A096024 A205980 * A205831 A206408 A238174

Adjacent sequences:  A206659 A206660 A206661 * A206663 A206664 A206665

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 11 2012

STATUS

approved

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Last modified January 18 19:59 EST 2021. Contains 340262 sequences. (Running on oeis4.)