A086683 - OEIS

%I #4 Jul 08 2018 21:29:50

%S 1,3,45,6579,10763361,169457722083,25015772614247325,

%T 34185618461516789943315,429210477536564292209765507601,

%U 49269609804781974438694405096704997875,51537752073201133103646184766360896456864366605,490093718158481239203594498957165010835856989328505008243

%N Number of n X n {-1,0,1} matrices modulo cyclic permutations of the rows.

%H Andrew Howroyd, <a href="/A086683/b086683.txt">Table of n, a(n) for n = 0..40</a>

%F a(n) = (1/n)*Sum_{ d divides n } phi(d)*3^(n^2/d) for n > 0.

%o (PARI) a(n) = if(n<1, n==0, sumdiv(n, d, eulerphi(d)*3^(n^2/d))/n);

%Y Cf. A086675, A060336.

%K nonn

%O 0,2

%A Yuval Dekel (dekelyuval(AT)hotmail.com), Jul 28 2003

%E a(0)=1 prepended and terms a(7) and beyond from _Andrew Howroyd_, Jul 08 2018