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 A186709 Number of quadratic residues (mod p) in the interval [2k+2,4k+2], for primes p=4k+3. 1
 0, 1, 1, 3, 4, 6, 9, 9, 10, 15, 14, 17, 16, 23, 22, 29, 25, 30, 34, 39, 36, 37, 41, 45, 48, 52, 49, 52, 52, 59, 62, 66, 72, 68, 78, 79, 80, 87, 90, 87 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS FORMULA a(n) = A104635(n) - A186708(n) = A186708(n) - A178154(n) = (A104635(n) - A178154(n))/2 = (A002145(n) - 2*A178154(n) -1)/4. PROG (PARI) forprime( p=1, 399, p%4==3|next; u=3; c=[1, 0]; for(i=2, p-2, bittest(u, i^2%p) & next; u+=1<<(i^2%p); c[i^2%p*2\p+1]++); print1(c[2]", ")) CROSSREFS Cf. A002145, A186708, A178154. Sequence in context: A186700 A028987 A284615 * A143037 A225059 A190899 Adjacent sequences:  A186706 A186707 A186708 * A186710 A186711 A186712 KEYWORD nonn AUTHOR M. F. Hasler, Feb 25 2011 STATUS approved

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