OFFSET
1,1
EXAMPLE
For n=6 the sum of 6th powers is [[3,0],[0,3]].
MATHEMATICA
matrices[n_] := matrices[n] = Flatten[Table[{{a, b}, {b, d}}, {a, n}, {b, n}, {d, n}], 2]; su[n_, k_] := su[n, k] = Mod[Sum[MatrixPower[matrices[n][[i]], k], {i, 1, Length[matrices[n]]}], n]; Table[If[! su[n, n] == {{0, 0}, {0, 0}}, Print[n]; n], {n, 1, 120}] // Union
CROSSREFS
KEYWORD
nonn,more
AUTHOR
José María Grau Ribas, Jan 31 2014
EXTENSIONS
a(12)-a(50) from Giovanni Resta, Feb 01 2014
STATUS
approved