OFFSET
1,1
COMMENTS
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MATHEMATICA
ok[p_]:=Reduce[Mod[x^3 - 21, p] == 0, x, Integers] =!= False; Select[Prime[Range[180]], ok] (* Vincenzo Librandi, Sep 11 2012 *)
PROG
(Magma) [p: p in PrimesUpTo(450) | exists(t){x : x in ResidueClassRing(p) | x^3 eq 21}]; // Vincenzo Librandi, Sep 11 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved