A232057 Numbers k such that S(24*(3*k-1)) <> 16*(3*k-1) mod 24*(3*k-1) where S(k) := Sum_{0<=a<n, 0<=b<n} (a+b*i)^n and i is the imaginary unit.

5, 19, 37, 47, 61, 75

Offset

1,1

Links

Table of n, a(n) for n=1..6.

Mathematica

fu[n_] := fu[n] = Mod[Sum[PowerMod[i + j I, n, n], {i, 0, n - 1}, {j, 0, n - 1}], n]; Table[If[! fu[24(3n - 1)]/(3n - 1) == 16, Print[n]; n], {n, 1, 40}]

Crossrefs

Cf. A230308, A230309, A230310, A232056.

Sequence in context: A289289 A213631 A242589 * A031093 A297750 A285226

Adjacent sequences: A232054 A232055 A232056 * A232058 A232059 A232060

Keyword

nonn,more,hard

Author

José María Grau Ribas, Nov 17 2013

Status

approved