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 A220863 #18 Jan 25 2014 16:39:17 %S A220863 -7,-8,-4,-3,-8,-4,-4,-8,-20,-4,-3,-4,-4,-8,-20,-4,-8,-4,-8,-7,-4,-3, %T A220863 -8,-4,-4,-4,-3,-8,-4,-4,-3,-8,-4,-8,-4,-3,-4,-8,-20,-4,-8,-4,-7,-4, %U A220863 -4,-3,-8,-3,-8,-4,-4,-7,-4,-8,-4,-20,-4,-3,-4,-4,-8,-4,-8,-11,-4,-4,-8,-4,-8,-4,-4,-7,-3,-4,-8 %N A220863 Choose smallest m>0 such that the n-th rational prime p splits in the imaginary quadratic extension field K = Q(sqrt(-m)); a(n) = discriminant(K). %C A220863 a(n) = discriminant of extension field defined in A220862. %D A220863 David A. Cox, "Primes of the Form x^2 + n y^2", Wiley, 1989, Cor. 5.17, p. 105. %F A220863 Let i = A220862(n). Then a(n) = i if i == 1 (mod 4), otherwise 4i. %Y A220863 Cf. A088192, A220861, A220862. %K A220863 sign %O A220863 1,1 %A A220863 _N. J. A. Sloane_, Dec 26 2012