A125613 - OEIS

%I #13 Dec 19 2024 19:06:12

%S 1,1,17,21,132,351,816,874,1104,4031,3286,8473,11726,11868,11233,

%T 24857,28143,38247,46766,40754,66722,65017,83249,120150,156364,173013,

%U 152955,184147,218763,245436,297053,327500,437030,413803,556217,488334,652335

%N Sum of the squares of the quadratic residues 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="/A125613/b125613.txt">Table of n, a(n) for n = 1..1000</a>

%e The quadratic residues of 7=prime(4) are 1, 2 and 4. Hence a(4)=1^2 + 2^2 + 4^2=21.

%t Table[Total[ResourceFunction["QuadraticResidues"][Prime[n]]^2],{n,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); t)

%Y Cf. A076409, A076410, A125613-A125618.

%K easy,nonn

%O 1,3

%A _Nick Hobson_, Nov 30 2006