OEIS A280831

[rwst]

What is the conjecture

Any nonnegative integer can be written as

$$ x^2 + y^2 + z^2 + w^2, \text{with $x,y,z,w$ nonnegative integers such that $x^4 + 1680y^3z$ is a square.} $$

See https://oeis.org/A280831. Zhi-Wei Sun has set a prize of RMB 1,680 (see his homepage).

Prerequisites needed

Status: open

Choose either option

• I plan on adding this conjecture to the repository
• This issue is up for grabs: I would like to see this conjecture added by somebody else

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[Yuvraj-cyborg]

@rwst hey i would like to work on this one