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%I #17 Nov 01 2017 12:23:10
%S 208,104968,71582944,54975633976,45035996274688,38430716856090160,
%T 33731189163354610720,30223145490393217217464,
%U 27509778650786228378836960,25353012004564610547932704768,23601349356976489220593165438048,22153799929748597900945512768786000
%N Number of distinct n X 5 toroidal 0..3 arrays.
%H Andrew Howroyd, <a href="/A184276/b184276.txt">Table of n, a(n) for n = 1..100</a>
%t T[n_, k_] := (1/(n*k))*Sum[Sum[EulerPhi[c]*EulerPhi[d]*4^(n*k/LCM[c, d]), {d, Divisors[k]}], {c, Divisors[n]}]; a[n_] := T[n, 5]; Array[a, 12] (* _Jean-François Alcover_, Nov 01 2017, after _Andrew Howroyd_ *)
%o (PARI) a(n) = my(k=5); (1/(n*k)) * sumdiv(n, c, sumdiv(k, d, eulerphi(c) * eulerphi(d) * 4^(n*k/lcm(c, d)))); \\ _Michel Marcus_, Nov 01 2017
%Y Column 5 of A184277.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 10 2011
%E Terms a(6) and beyond from _Andrew Howroyd_, Sep 27 2017
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