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Will Jagy
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As is the case (analogous) for the sum of three squares, for the number $1$ we do not get the same ratios as for other numbers $1 \pmod {72},$ those being together in lines with the output N 1 in the column for %72

As is the case (analogous) for the sum of three squares, for the number $1$ we do not get the same ratios as for other numbers $1 \pmod {72},$ those being together in lines with the output N 1 in the column for %72

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Will Jagy
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The class numbers are for positive binary quadratic forms. See Is there a simple way to compute the number of ways to write a positive integer as the sum of three squares? and Gerry's reference in comment, as well as request for clarification from John Voight (which eventually worked out).

Made a little summary: the ratios $(r_0/h(4M), r_1/h(4M))$$(r_0/h(-4M), r_1/h(-4M))$ are split three ways when $\gcd(M,6) = 1.$ We get ratios $(12,4)$ when $M \equiv 1, 13,25,37,49,61 \pmod {72},$ which is all $M \equiv 1 \pmod {12}.$ We get ratios $(24,16)$ when $M \equiv 7,31,55 \pmod {72},$ which is all $M \equiv 7 \pmod {24}.$We get ratios $(16,8)$ when $M \equiv 19,43,67 \pmod {72},$ which is all $M \equiv 19 \pmod {24}.$

Made a little summary: the ratios $(r_0/h(4M), r_1/h(4M))$ are split three ways when $\gcd(M,6) = 1.$ We get ratios $(12,4)$ when $M \equiv 1, 13,25,37,49,61 \pmod {72},$ which is all $M \equiv 1 \pmod {12}.$ We get ratios $(24,16)$ when $M \equiv 7,31,55 \pmod {72},$ which is all $M \equiv 7 \pmod {24}.$We get ratios $(16,8)$ when $M \equiv 19,43,67 \pmod {72},$ which is all $M \equiv 19 \pmod {24}.$

The class numbers are for positive binary quadratic forms. See Is there a simple way to compute the number of ways to write a positive integer as the sum of three squares? and Gerry's reference in comment, as well as request for clarification from John Voight (which eventually worked out).

Made a little summary: the ratios $(r_0/h(-4M), r_1/h(-4M))$ are split three ways when $\gcd(M,6) = 1.$ We get ratios $(12,4)$ when $M \equiv 1, 13,25,37,49,61 \pmod {72},$ which is all $M \equiv 1 \pmod {12}.$ We get ratios $(24,16)$ when $M \equiv 7,31,55 \pmod {72},$ which is all $M \equiv 7 \pmod {24}.$We get ratios $(16,8)$ when $M \equiv 19,43,67 \pmod {72},$ which is all $M \equiv 19 \pmod {24}.$

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Will Jagy
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You have a good answer; hereHere are some computations about primitive representations by two forms, $g_0$ is the underlying $x^2 + y^2 + 3 z^2 + xy,$ while $g_1$ is your $x^2 + 3 y^2 + 3 z^2.$ I was a little surprised to find a distinction requiring mod 72, mod 36 was not enough. Compare $7 \pmod {72}$ to $43 \pmod {72}.$ Alright, it amounts to $\pmod {24}.$ When I have time I will compute the cases divisible by 2 or 3 or both.

You have a good answer; here are some computations about primitive representations by two forms, $g_0$ is the underlying $x^2 + y^2 + 3 z^2 + xy,$ while $g_1$ is your $x^2 + 3 y^2 + 3 z^2.$ I was a little surprised to find a distinction requiring mod 72, mod 36 was not enough. Compare $7 \pmod {72}$ to $43 \pmod {72}.$ Alright, it amounts to $\pmod {24}.$ When I have time I will compute the cases divisible by 2 or 3 or both.

Here are some computations about primitive representations by two forms, $g_0$ is the underlying $x^2 + y^2 + 3 z^2 + xy,$ while $g_1$ is your $x^2 + 3 y^2 + 3 z^2.$ I was a little surprised to find a distinction requiring mod 72, mod 36 was not enough. Compare $7 \pmod {72}$ to $43 \pmod {72}.$ Alright, it amounts to $\pmod {24}.$ When I have time I will compute the cases divisible by 2 or 3 or both.

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Will Jagy
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Will Jagy
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