A184275 Number of distinct n X 4 toroidal 0..3 arrays.

70, 8296, 1398500, 268447936, 54975633976, 11728126132976, 2573485510942780, 576460752706101376, 131176846748288854980, 30223145490448192851232, 7033750223212787748164020, 1650586719047191292234702976, 390046338531762979375904093800

Offset: 1

Author

R. H. Hardin, Jan 10 2011

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..100

Crossrefs

Column 4 of A184277.

Programs

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, 4]; Array[a, 13] (* Jean-François Alcover, Oct 31 2017, after Andrew Howroyd *)

Extensions

Terms a(7) and beyond from Andrew Howroyd, Sep 27 2017