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A184275
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Number of distinct n X 4 toroidal 0..3 arrays.
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2
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70, 8296, 1398500, 268447936, 54975633976, 11728126132976, 2573485510942780, 576460752706101376, 131176846748288854980, 30223145490448192851232, 7033750223212787748164020, 1650586719047191292234702976, 390046338531762979375904093800
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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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, 4]; Array[a, 13] (* Jean-François Alcover, Oct 31 2017, after Andrew Howroyd *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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