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%I #13 Dec 20 2024 02:15:36
%S 0,4,13,70,253,299,680,1235,2691,3683,6169,7733,10414,13717,22278,
%T 23373,38586,35563,51255,76041,60298,96222,103916,110894,143172,
%U 165337,206000,218494,206991,229164,377698,413305,410726,471766,535357,647941,625331
%N Sum of the squares of the quadratic nonresidues of prime(n).
%C For all n > 3, prime(n) divides a(n).
%D D. M. Burton, Elementary Number Theory, McGraw-Hill, Sixth Edition (2007), p. 185.
%H Nick Hobson, <a href="/A125617/b125617.txt">Table of n, a(n) for n = 1..1000</a>
%e The quadratic nonresidues of 7=prime(4) are 3, 5 and 6. Hence a(4) = 3^2 + 5^2 + 6^2 = 70.
%t Table[Total[Complement[Range[p-1],Union[Table[PowerMod[k, 2, p], {k, p}]]]^2],{p,Prime@Range[37]}] (* _James C. McMahon_, Dec 19 2024 *)
%o (PARI) vector(37, n, p=prime(n); t=1; for(i=2, (p-1)/2, t+=((i^2)%p)^2); p*(p-1)*(2*p-1)/6-t)
%Y Cf. A076409, A076410, A125613-A125618.
%K easy,nonn,changed
%O 1,2
%A _Nick Hobson_, Nov 30 2006