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 A003646 M0077 #17 Apr 14 2019 10:42:26 %S A003646 1,1,2,1,1,2,2,2,1,2,1,2,1,2,1,2,2,4,1,2,2,1,2,2,2,2,1,2,2,1,1,2,4,1, %T A003646 1,4,2,2,2,4,1,4,2,4,1,2,4,1,2,4,4,2,1,2,1,2,2,2,1,1,2,4,4,2,2,2,4,4, %U A003646 3,2,1,2,2,1,2,2,2,3,4,2,2,1,4,1,4,1,2,4,1,2,2,4,2,4,1,6,1,6,4,2,2,1,2,2,4 %N A003646 Class number of binary quadratic forms with fundamental discriminant A003658(n),n>=2. %D A003646 D. A. Buell, Binary Quadratic Forms. Springer-Verlag, NY, 1989, pp. 236, 241. %D A003646 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A003646 S. R. Finch, <a href="http://www.people.fas.harvard.edu/~sfinch/">Class number theory</a> %H A003646 Steven R. Finch, <a href="/A000924/a000924.pdf">Class number theory</a> [Cached copy, with permission of the author] %H A003646 Wolfdieter Lang, <a href="/A003646/a003646.pdf">Table for a(n), n=2, ..., 92 (see Part 2).</a> %Y A003646 Cf. A087048, A079896. %K A003646 nonn %O A003646 2,3 %A A003646 _N. J. A. Sloane_, _Mira Bernstein_