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.
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
(PARI) a(n) = (n^9 - n^5)/4 \\ Michel Marcus, Mar 04 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Srikanth K S, Mar 27 2010
EXTENSIONS
More terms from Michel Marcus, Mar 04 2013
STATUS
approved