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A206680 Number of (n+1) X 4 0..2 arrays with every 2 X 3 or 3 X 2 subblock having an unequal number of clockwise and counterclockwise edge increases. 1
1404, 9792, 89022, 645144, 5747676, 41876592, 373903296, 2722587120, 24304785252, 176985022704, 1579981448832, 11505224983296, 102709417207548, 747917148492864, 6676804424256600, 48619655397737136, 434037286978243404 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A206685.

LINKS

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

FORMULA

Empirical: a(n) = 60*a(n-2) + 332*a(n-4) - 366*a(n-6) - 3833*a(n-8) + 2454*a(n-10) + 1844*a(n-12) + 3288*a(n-14) + 9008*a(n-16) - 864*a(n-18) for n>19.

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Sequence in context: A178271 A271579 A271712 * A022058 A107522 A158764

Adjacent sequences:  A206677 A206678 A206679 * A206681 A206682 A206683

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 11 2012

STATUS

approved

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Last modified August 10 14:50 EDT 2020. Contains 336381 sequences. (Running on oeis4.)