Re: question on class number for a certain n
American Citizen <[email protected]> Wed, 19 Nov 2025 15:14:44 -0800
| Newsgroups | gmane.comp.mathematics.pari.user |
|---|---|
| Message-ID | <[email protected]> |
Max: I checked using your p3(n) function, and it indeed matches my results for the first 237 relative maximums as N gradually climbs in value. Thank you for posting this Randall On 11/19/25 14:37, Max Alekseyev wrote: > Function p3(n) in the attached code works for all n. > > Regards, > Max > > > > On Wed, Nov 19, 2025 at 3:24 PM Bill Allombert > <[email protected]> wrote: > > On Wed, Nov 19, 2025 at 10:16:28AM +0100, Bill Allombert wrote: > > On Tue, Nov 18, 2025 at 10:59:53PM -0800, American Citizen wrote: > > > 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. > > > subsequent post. Can r_3(n) be found? > > > > This is a classical formula, but beware, it count all ordered > triples (x,y,z) > > in Z^3, so for example for n=17 there are 48 solutions instead of 2. > > I have found a formula (also for n>4 squarefree) > that only count positive increasing triples 0<=a<=b<=c. > > The idea is to count 'exceptional' representations separately, > that is the representations > that include repeated terms or the number 0, and use linear algebra. > > ? cnt(416666) > %2 = 339 > > Cheers, > Bill >