# Since AI (Claude) just helped find the new infinite family $a^4+b^4+c^4+d^4 = (a+27b+27c+27d)^4$, should we expect more similar discoveries soon?

> Source: <https://mathoverflow.net/questions/514415/since-ai-claude-just-helped-find-the-new-infinite-family-a4b4c4d4-a>
> Published: 2026-08-18 10:54:44+00:00

Back in the pre-AI years of 2008, Jacobi-Madden found the infinite family,

$$a^4+b^4+c^4+d^4 = (a+b+c+d)^4$$

Just a few days ago, **Matej Veselovac** in an [MSE post](https://math.stackexchange.com/a/5146910/4781) found the **new** family,

$$a^4+b^4+c^4+d^4 = (a+27b+27c+27d)^4$$

as well as **eight** more. Jacobi had to peruse only the first 30 solutions of the $(4,1,4)$ to find his first example. But since Matej had to wade through more than **45,000** solutions to find patterns, it seems AI can prove useful when data-mining an ocean of data.

**I. The Story**

Matej and I met while data-mining Eugene Go's answer to David's question in MSE, about a database of around 45,000 primitive solutions to $a^4+b^4+c^4+d^4 = e^4$ with $e<10^7$. I was low-tech, using Google's free spreadsheet. Matej, on the other hand, was more high-tech and used an AI (Claude). We got nowhere.

After I edited Matej's answer, I suggested he ask Claude to to find "interesting" linear relations between ALL terms $(a,b,c,d,e)$ similar to the Jacobi-Madden. Turns out Claude was up to the challenge. For example, given

$$329580^4 + 32420^4 + 1911244^4 + 2018095^4 = 2339217^4$$

Claude found the simple relation,

$$\frac{-a+e}{-b-c+d}= \frac{-329580 + 2339217}{-32420 - 1911244 + 2018095}=\color{red}{3^3}$$

* How is a human being supposed to find that?!* It is a sea of

$$\frac{a+e}{b+c+d} = k^3$$

where $k$ is a * tiny* rational number like $k=3,\,5/4,\,5/3,\,5,$ etc. (

**II. The equation**

Matej reached out to me as he knew I did work on the $(4,1,3)$ and $(4,1,4)$. Their proof seems a bit complicated and technical, but it turns out there was a simple *algebraic identity behind it*. In my posts, there's always a *quadratic form* or an *elliptic curve*, and it turns out the nine families were no different. Given,

$$1+x^4+y^4+z^4 = \big(1+k^3(x+y+z)\big)^4$$

Do the substitutions, $x = \frac{p+q}2,\; y=\frac{p-q}2,\; z = k+(h-1)(k+p)$, where $\color{blue}h$ is a parameter to be given later. We get the biquadratic in $q$,

$$q^4+Aq^2+B=0$$

The expressions for $(A,B)$ are quite long but Mathematica can quickly find them. The solution $q$ is the important point,

$$4q^2 = -12p^2\color{red}{\pm8}(k+p)\sqrt{D^2}$$ $$D^2 = 8h (k^2 - k p + p^2) + 12 h^2(k^6 - p^2) + 8h^3 (k + p) (k^9 + p) + 2h^4( k^{12}-1) (k + p)^2$$

and works for * any* three arbitrary parameters $(h,k,p)$.

But we wish to have rational $q$. Once $(h,k)$ are given, then the second equation fortunately is only a quadratic in $p$ to be made a square, easily done by *quadratic forms* using an initial solution. Substituting this quadratic form into the first equation which is also a quadratic in $p$, then one naturally gets $2\times2 = 4$ or,

$$q^2 = \text{quartic polynomial}$$

which is just a recipe for an *elliptic curve*.

**III. Example**

The smallest case Claude found was,

$$1+x^4+y^4+z^4 = \big(1+27(x+y+z)\big)^4$$

so $k=3$ and $(x,y,z) = (1602/2671,\, -9498/13355,\, 306/2671)$. The parameter $h$ is defined as,

$$h = \frac{x+y+z}{n+x+y}$$

Hence, $h = -1835/1837 + 1 = 2/1837.\,$ Since,

$$(x,y) = \left(1602/2671,\; -9498/13355\right) = \left(\frac{p+q}2,\;\frac{p-q}2\right)$$

therefore $(p,q) = (-1488/13355, 17508/13355)$ and polynomial $p$ is,

$$p = -\frac{1488}{13355} + \frac{5511 (48044056139 + 1242748 r)}{13355 (r^2 - 6190029774)}$$

Substituting polynomial $p$ into the formula in the previous section and using the *negative* case of $\pm8$, we get the quartic in $r$ to be made a square,

$$q^2 = -R^2(18958669594580211381729967107 + 1093490321304049798772416r + 15172317493269316128r^2 + 3306770731944r^3 + 35534992r^4)$$

where $R = \dfrac{3}{13355 (r^2 - 6190029774)}$. Let $r =-48044056139/1242748$ and we recover,

$$q^2 = \left(\frac{17508}{13355}\right)^2$$

This quartic is birationally equivalent to an *elliptic curve with positive rank*, hence there are infinitely many rational $r_n$. This method can be generalized to * all* nine families.

**IV. Question**

**Q:** Can AI help find new infinite families $a^4+b^4+c^4+d^4 = e^4$ were the terms are now in a *non-linear* relation? In general, given a Diophantine equation with thousands of solutions, will we reach a point where AI can find patterns in the data that the human mind can't, and we just step in to formally confirm the pattern?

**P.S.** If the question is too difficult, I'll be happy to be given the first few small solutions to,

$$a^4+b^4+c^4+d^4 = (a+27b+27c+27d)^4 = e^4$$

with $e<10^{20}$ using the elliptic curve above. (I don't think that $r_n$ was the smallest one while the table of 63 solutions for the Jacobi-Madden $a^4+b^4+c^4+d^4 = (a+b+c+d)^4 = e^4$ with $e<10^{18}$ is [here](https://math.stackexchange.com/q/4864970/4781).)
