

A174686


Number of equivalence classes of 3 X 3 matrices filled with n colors so that no two rotations are identical.


0



120, 4860, 65280, 487500, 2517480, 10084200, 33546240, 96840360, 249975000, 589446660, 1289882880, 2651032020, 5165127240, 9610650000, 17179607040, 29646614160, 49589350200, 80671305420, 127999200000, 198568990620, 301816016040, 450286556280, 660449894400
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OFFSET

2,1


COMMENTS

Each class contains a set of 4 matrices so that all of them can be obtained by successive rotation but no two are identical.


LINKS



FORMULA

a(n) = (n^9  n^(floor(9/2) + 1))/4. More generally for any m X m matrix f(n,m) = (n^(m^2)  n^(m^2/2))/4 if m is even, and f(n,m) = (n^(m^2)  n^(floor(m^2/2)+1))/4 if m is odd.


PROG



CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



