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A257303 Number of 5th power nonresidues modulo n. 3

%I #10 Apr 24 2015 18:29:29

%S 0,0,0,1,0,0,0,3,2,0,8,3,0,0,0,7,0,4,0,5,0,16,0,9,20,0,8,7,0,0,24,15,

%T 24,0,0,15,0,0,0,15,32,0,0,35,10,0,0,21,6,40,0,13,0,16,40,21,0,0,0,15,

%U 48,48,14,30,0,48,0,17,0,0,56,37,0,0,60,19,56,0,0,35,26,64,0,21,0,0,0,73,0

%N Number of 5th power nonresidues modulo n.

%C a(n) is the number of values r, 0<=r<n, such that, for p=5 and for any m>=0, (m^p)%n != r.

%H Stanislav Sykora, <a href="/A257303/b257303.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = n-A052274(n).

%F Satisfies a(n) <= n-3 (residues 0, 1, and n-1 are always present).

%t Table[Length[Complement[Range[n - 1], Union[Mod[Range[n]^5, n]]]], {n, 100}] (* _Vincenzo Librandi_, Apr 20 2015 *)

%o (PARI) nrespowp(n,p) = {my(v=vector(n),d=0);

%o for(r=0,n-1,v[1+(r^p)%n]+=1);

%o for(k=1,n,if(v[k]==0,d++));

%o return(d);}

%o a(n) = nrespowp(n,5)

%Y Cf. A095972 (p=2), A257301 (p=3), A257302 (p=4).

%K nonn

%O 1,8

%A _Stanislav Sykora_, Apr 19 2015

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Last modified April 23 18:16 EDT 2024. Contains 371916 sequences. (Running on oeis4.)