

A200045


Number T(n,m) of ways of 4coloring an n X m grid so that there is no rectangle with all 4 corners the same color.


3



4, 16, 252, 64, 3912, 228984, 256, 59928, 12870096, 2545607472, 1024, 906912, 696448224, 465659203104, 272454472598400, 4096, 13571712, 36376835616, 79102304162784, 140221913588582784
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OFFSET

1,1


COMMENTS

The rectangles have sides parallel to the x and yaxes.


LINKS

Table of n, a(n) for n=1..20.
J. D. Davies, Number of unique rectanglefree 4colourings for an nxm grid


EXAMPLE

Triangle starts:
4;
16, 252;
64, 3912, 228984;
256, 59928, 12870096, 2545607472;
1024, 906912, 696448224, 465659203104, 272454472598400;
...


CROSSREFS

Cf. A252778, A252780, A252839.
Sequence in context: A271267 A232840 A113905 * A099202 A139288 A152921
Adjacent sequences: A200042 A200043 A200044 * A200046 A200047 A200048


KEYWORD

nonn,tabl,more


AUTHOR

Jason Davies, Nov 14 2011


EXTENSIONS

T(6,5) from Jason Davies, Nov 08 2012


STATUS

approved



