This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A186709 #7 Jul 14 2012 11:32:34 %S A186709 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, %T A186709 52,49,52,52,59,62,66,72,68,78,79,80,87,90,87 %N A186709 Number of quadratic residues (mod p) in the interval [2k+2,4k+2], for primes p=4k+3. %F A186709 a(n) = A104635(n) - A186708(n) = A186708(n) - A178154(n) = (A104635(n) - A178154(n))/2 = (A002145(n) - 2*A178154(n) -1)/4. %o A186709 (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]", ")) %Y A186709 Cf. A002145, A186708, A178154. %K A186709 nonn %O A186709 1,4 %A A186709 _M. F. Hasler_, Feb 25 2011