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 A014599 #13 May 15 2021 04:50:27 %S A014599 1,1,1,2,1,3,1,3,2,4,1,5,2,4,3,4,1,7,2,5,3,6,2,8,2,5,3,8,2,10,2,5,5,6, %T A014599 3,10,2,7,4,10,1,11,4,6,5,8,2,13,4,9,4,6,3,14,4,7,5,12,2,15,3,6,7,12, %U A014599 4,13,2,11,4,12,3,14,4,8,8,10,3,19,4,10,4,12,3,18,6,7,5,12,4,19 %N A014599 Class numbers h(D) of imaginary quadratic fields with discriminant D=1-4*n. %C A014599 Also class number, or number of equivalence classes of positive definite binary quadratic forms of discriminant -(4n-1). - _N. J. A. Sloane_, May 28 2014 %D A014599 D. A. Buell, Binary Quadratic Forms. Springer-Verlag, NY, 1989, pages 19 and 224-230. - _N. J. A. Sloane_, May 28 2014 [Only the squarefree cases appear on pp. 224-230] %D A014599 H. Cohen, Course in Computational Alg. No. Theory, Springer, 1993, pp. 514-5. %H A014599 N. J. A. Sloane, <a href="/A014599/b014599.txt">Table of n, a(n) for n = 1..10000</a> %o A014599 (PARI) a(n) = qfbclassno(1-4*n) %Y A014599 See A000003 for discriminant -4n. %K A014599 nonn %O A014599 1,4 %A A014599 Eric Rains (rains(AT)caltech.edu)