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A206341 Number of (n+1)X7 0..3 arrays with every 2X2 subblock having nonzero determinant and commuting with every horizontal or vertical neighbor 1
880, 1589, 2030, 4711, 6090, 14181, 18258, 42351, 54654, 126861, 163842, 380391, 491406, 1141143, 1474206, 3423417, 4422606, 10270239, 13267806, 30810705, 39803406, 92432103, 119410206, 277296297, 358230606, 831888879, 1074691806 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 6 of A206343

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) +3*a(n-2) -3*a(n-3) for n>15

EXAMPLE

Some solutions for n=4

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

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

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

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

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

CROSSREFS

Sequence in context: A063051 A190030 A118799 * A024393 A006052 A105976

Adjacent sequences:  A206338 A206339 A206340 * A206342 A206343 A206344

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 06 2012

STATUS

approved

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Last modified May 29 16:53 EDT 2017. Contains 287252 sequences.