OFFSET
4,1
COMMENTS
Always an integer for primes > 5.
REFERENCES
D. M. Burton, Elementary Number Theory, McGraw-Hill, Sixth Edition (2007), p. 185.
LINKS
Nick Hobson, Table of n, a(n) for n = 4..1003
FORMULA
a(n) = A125613(n)/prime(n).
EXAMPLE
The quadratic residues of 7=prime(4) are 1, 2 and 4. Hence a(4) = (1^2 + 2^2 + 4^2)/7 = 3.
PROG
(PARI) vector(47, m, p=prime(m+3); t=1; for(i=2, (p-1)/2, t+=((i^2)%p)^2); t/p)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Nick Hobson, Nov 30 2006
STATUS
approved