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A282723 Let p = n-th prime == 3 mod 8; a(n) = sum of quadratic residues mod p. 2
1, 22, 76, 430, 767, 1072, 1577, 2675, 3930, 4587, 6520, 7518, 10761, 12258, 14809, 19527, 23025, 26811, 29148, 35247, 41900, 47844, 52771, 57938, 61377, 66944, 73845, 76568, 79940, 83941, 94088, 102237, 104781, 114744, 117470, 134498, 152678, 161389, 167881, 181249, 193377, 204075, 221598, 228185 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..2500

Aebi, Christian, and Grant Cairns. Sums of Quadratic residues and nonresidues, arXiv preprint arXiv:1512.00896 (2015).

MAPLE

with(numtheory):

Ql:=[]; Qu:=[]; Q:=[]; Nl:=[]; Nu:=[]; N:=[]; Th:=[];

for i1 from 1 to 300 do

p:=ithprime(i1);

if (p mod 8) = 3 then

ql:=0; qu:=0; q:=0; nl:=0; nu:=0; n:=0;

for j from 1 to p-1 do

if legendre(j, p)=1 then

q:=q+j;

if j<p/2 then ql:=ql+j; else qu:=qu+j; fi;

else

n:=n+j;

if j<p/2 then nl:=nl+j; else nu:=nu+j; fi;

fi;

od;

Ql:=[op(Ql), ql];

Qu:=[op(Qu), qu];

Q:=[op(Q), q];

Nl:=[op(Nl), nl];

Nu:=[op(Nu), nu];

N:=[op(N), n];

Th:=[op(Th), q+ql];

fi;

od:

Ql; Qu; Q; Nl; Nu; N; Th; # A282721 - A282727

MATHEMATICA

Table[Table[Mod[a^2, p], {a, 1, (p-1)/2}]//Total, {p, Select[Prime[Range[100]], Mod[#, 8] == 3 &]}] (* Vincenzo Librandi, Feb 21 2017 *)

CROSSREFS

Cf. A282035-A282043 and A282721-A282727.

Sequence in context: A080861 A241521 A143838 * A003908 A075252 A253304

Adjacent sequences:  A282720 A282721 A282722 * A282724 A282725 A282726

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Feb 20 2017

STATUS

approved

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Last modified June 24 18:43 EDT 2021. Contains 345419 sequences. (Running on oeis4.)