[seqfan] Re: Generally known (to those who know of such things)

[Maximilian Hasler]

On Sun, Nov 22, 2009 at 7:38 PM,  <franktaw at netscape.net> wrote:
> Wikipedia lists two meanings for "class number"; neither matches this
> one.

it should match this :
http://en.wikipedia.org/wiki/Class_number_(number_theory)#Class_numbers_of_quadratic_fields

The confusion might arise from the definition of A002143.
It should indeed be improved. What is meant is :
A002143(k) = h(-A002145(k))
= class number of the k-th prime /of the form/ 4n-1 (or 4n+3)

e.g. A002143(4) = 1 is the class number of -19, the 4-th prime = 3 mod 4

Maximilian