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%I #8 May 29 2024 13:47:05
%S 1,3,16,84,480,2792,16807,102900,640528,4035120,25679568,164775800,
%T 1064714400,6920635197,45214871360,296722542900,1954878268800,
%U 12923917122536,85705978837392,569944757250960,3799631728452112,25388448354582216,169992219503608176
%N Number of monic irreducible polynomials over GF(7) with fixed nonzero trace.
%H Frank Ruskey, <a href="http://combos.org/Tpoly">Number of monic irreducible polynomials over GF(q) with given trace</a>
%F a(n) = 1/(7*n) * Sum_{d|n, gcd(d,7)=1} mu(d) * 7^(n/d).
%o (PARI) a(n) = sumdiv(n, d, (gcd(d, 7)==1)*(moebius(d)*7^(n/d)))/(7*n);
%Y Column 7 of A110540.
%K nonn
%O 1,2
%A _Seiichi Manyama_, May 29 2024