American Citizen on Wed, 19 Nov 2025 07:59:59 +0100


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question on class number for a certain n


Hi all:

I have been looking at representations of integers as the sum of 3 squares and things are very interesting.

A quote from Wolfram Math states

The number of solutions of

(36)   x^2 + y^2 + z^2 = n

for a given n without restriction on the signs or relative sizes of x, y, and z is given by r_3(n). Gauss proved that if n is squarefree and n>4, then

(37)  r_3(n) =  24h(-n)  for n=3 (mod 8);
             =  12h(-4n) for n=1,2,5,6 (mod 8);
             =   0       for n=7 (mod 8)

(Arno 1992), where h(x) is the class number of x.

The generating function for r_3(n) is given by

(38)  sum_(n=0)^(infty)r_3(n)x^n = theta_3^3(x)
(39)   = 1+6x+12x^2+8x^3+6x^4+24x^5+24x^6+12x^8+30x^9+...

Example:

   n = 6844361

Class number h(-4n) is what ???
There are a lot of triads for this number n. I will share what I found in a subsequent post. Can r_3(n) be found?

Randall