OFFSET
1,20
COMMENTS
Sum of the n-th powers of the invertible elements of Z[i]/nZ[i].
LINKS
Hans Havermann, Table of n, a(n) for n = 1..5000
MATHEMATICA
Sp[n_, k_] := Mod[Sum[If[GCD[a^2 + b^2, n] == 1, PowerMod[(a + b I), k, n], 0], {a, n}, {b, n}], n]; Table[ Sp[n, n] , {n, 1, 74}]
CROSSREFS
KEYWORD
nonn
AUTHOR
José María Grau Ribas, Oct 07 2015
STATUS
approved