

A183814


1/81 the number of (n+1) X 4 0..2 arrays with no 2 X 2 subblock being a reflection across the shared element pair of any horizontal or vertical neighbor.


1



64, 3256, 163208, 8231592, 414246824, 20864057480, 1050517114472, 52900274426120, 2663752907479720, 134133403972622152, 6754253376412941416, 340109468142471752968, 17126149629153540430376, 862384378029691966195144
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OFFSET

1,1


COMMENTS

Column 3 of A183819.


LINKS

R. H. Hardin, Table of n, a(n) for n = 1..41


FORMULA

Empirical: a(n) = 43*a(n1) + 560*a(n2)  10054*a(n3) + 24480*a(n4) + 45920*a(n5).
Empirical g.f.: 8*x*(8 + 63*x  1580*x^2 + 4218*x^3 + 7624*x^4) / (1  43*x  560*x^2 + 10054*x^3  24480*x^4  45920*x^5).  Colin Barker, Apr 04 2018


EXAMPLE

Some solutions with upper left block zero for 3 X 4:
..0..0..0..1....0..0..0..1....0..0..0..2....0..0..2..2....0..0..0..2
..0..0..1..1....0..0..1..2....0..0..1..1....0..0..1..0....0..0..2..0
..2..1..1..1....2..0..2..1....2..2..2..1....2..0..0..1....0..2..0..0


CROSSREFS

Cf. A183819.
Sequence in context: A264094 A181249 A260857 * A281343 A298286 A299358
Adjacent sequences: A183811 A183812 A183813 * A183815 A183816 A183817


KEYWORD

nonn


AUTHOR

R. H. Hardin, Jan 07 2011


STATUS

approved



