OFFSET
1,1
MATHEMATICA
S[n_] := Mod[Sum[If[GCD[i, n] == 1, PowerMod[i, n, n], 0], {i, 1, n}], n]; Select[Range[1200], ! S[#] == 0 &]
CROSSREFS
KEYWORD
nonn
AUTHOR
José María Grau Ribas, Dec 09 2013
STATUS
approved