A054752 - OEIS

%I #9 Apr 15 2021 15:21:36

%S 1,5,120,252375,19076074375,37252918396015625,

%T 1818989403666496277343750,2220446049250331744551658935546875,

%U 67762635780344027129112510010600128173828125,51698788284564229679463057470911735435947895050048828125

%N Number of inequivalent n X n matrices over GF(5) under action of dihedral group of the square D_4.

%H Andrew Howroyd, <a href="/A054752/b054752.txt">Table of n, a(n) for n = 0..25</a>

%F a(n) = 1/8*(5^(n^2) + 2*5^(n^2/4) + 3*5^(n^2/2) + 2*5^((n^2+n)/2)) if n is even;

%F a(n) = 1/8*(5^(n^2) + 2*5^((n^2+3)/4) + 5^((n^2+1)/2) + 4*5^((n^2+n)/2)) if n is odd.

%Y Column k=5 of A343097.

%Y Cf. A054247.

%K easy,nonn

%O 0,2

%A _Vladeta Jovovic_, May 15 2000

%E Terms a(9) and beyond from _Andrew Howroyd_, Apr 15 2021