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A184272
Number of distinct n X n toroidal 0..3 arrays.
3
4, 76, 29184, 268447936, 45035996274688, 131176846752109387776, 6467605103205252048452583424, 5316911983139663492479919370381869056, 72172920362019897195243695442781187577923764224, 16069380442589902755419620923449655543228876820136712994816
OFFSET
1,1
LINKS
MATHEMATICA
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, n]; Array[a, 10] (* Jean-François Alcover, Oct 31 2017, after Andrew Howroyd *)
CROSSREFS
Diagonal of A184277.
Sequence in context: A325214 A118193 A052271 * A080989 A006267 A273952
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 10 2011
EXTENSIONS
Terms a(6) and beyond from Andrew Howroyd, Sep 27 2017
STATUS
approved