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A125616 (Sum of the quadratic nonresidues of prime(n)) / prime(n). 2
1, 2, 3, 3, 4, 5, 7, 7, 9, 9, 10, 11, 14, 13, 16, 15, 17, 21, 18, 22, 22, 22, 24, 25, 28, 28, 27, 28, 34, 35, 34, 36, 37, 41, 39, 41, 47, 43, 47, 45, 54, 48, 49, 54, 54, 59, 59, 57, 58, 67, 60, 66, 64, 72, 67, 73, 69, 70, 72, 73, 78, 87, 78, 79, 84, 84, 89, 87, 88, 99, 96, 93, 96 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,2

COMMENTS

Always an integer for primes > 3.

REFERENCES

D. M. Burton, Elementary Number Theory, McGraw-Hill, Sixth Edition (2007), p. 185.

LINKS

N. Hobson, Table of n, a(n) for n = 3..1000

N. Hobson, Home page (listed in lieu of email address)

FORMULA

a(n)=A125615(n)/prime(n).

If prime(n) = 4k+1 then a(n) = k = A076410(n).

EXAMPLE

The quadratic nonresidues of 7=prime(4) are 3, 5 and 6. Hence a(4)=(3+5+6)/7=2.

PROG

(PARI) vector(73, m, p=prime(m+2); t=1; for(i=2, (p-1)/2, t+=((i^2)%p)); (p-1)/2-t/p)

CROSSREFS

Cf. A002143, A076409, A076410, A125613-A125618.

Sequence in context: A118302 A205216 A017853 * A141472 A029034 A115339

Adjacent sequences:  A125613 A125614 A125615 * A125617 A125618 A125619

KEYWORD

easy,nonn

AUTHOR

Nick Hobson Nov 30 2006

STATUS

approved

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Last modified May 24 14:54 EDT 2013. Contains 225624 sequences.