A074014 - OEIS

%I #19 May 13 2024 02:12:59

%S 1,1,13,49,301,2401,16807,117649,825601,5764801,40339201,282475249

%N Number of elements of GF(7^n) with trace 0 and subtrace 0.

%H Frank Ruskey, <a href="http://combos.org/TSGF7">Number of Elements of GF(7^n) with given trace and subtrace</a>

%o (Sage)

%o def a(n):

%o     if n==1: return 1

%o     ans = 0

%o     for x in GF(7^n):

%o         if x.charpoly().coefficients(sparse=False)[-3:-1]==[0, 0]: ans += 1

%o     return ans  # _Robin Visser_, May 13 2024

%Y Cf. A074015, A074016, A074017, A074018, A074019, A074020, A074021, A074022, A074023.

%K nonn,more

%O 1,3

%A _Frank Ruskey_ and Nate Kube, Aug 19 2002

%E a(8)-a(12) from _Robin Visser_, May 13 2024