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A206339 Number of (n+1) X 5 0..3 arrays with every 2 X 2 subblock having nonzero determinant and commuting with every horizontal or vertical neighbor. 1
296, 534, 682, 1581, 2034, 4711, 6078, 14101, 18210, 42271, 54606, 126799, 163806, 380385, 491406, 1141143, 1474206, 3423417, 4422606, 10270239, 13267806, 30810705, 39803406, 92432103, 119410206, 277296297, 358230606, 831888879 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 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>13.

Empirical g.f.: x*(296 + 238*x - 740*x^2 + 185*x^3 + 9*x^4 - 20*x^5 + 8*x^6 - 8*x^7 + 8*x^8 - 8*x^9 + 8*x^10 + 10*x^11 + 2*x^12) / ((1 - x)*(1 - 3*x^2)). - Colin Barker, Jun 15 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Cf. A206343.

Sequence in context: A237803 A238512 A003780 * A107924 A224170 A223861

Adjacent sequences:  A206336 A206337 A206338 * A206340 A206341 A206342

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 06 2012

STATUS

approved

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Last modified January 26 23:05 EST 2020. Contains 331289 sequences. (Running on oeis4.)