Lagrange's four-square theorem - Wikipedia

Table 1 from Extended Lagrange's four-square theorem

Jacobi's four-square theorem - Wikipedia

What's so interesting about squared numbers? Lagrange's Four Square Theorem

5. * In the following sequence of problems, we will

SOLVED: Theorem 8.35 (Lagrange's Four-Square Theorem) then n can be expressed as the sum If n is a number; of four squares: natural lattice A in 4-space is a set of the

SOLVED: 8.35 (Lagrange's Four-Square Theorem) If n is a natural number, it can be expressed as the sum of four squares. A lattice in 4-space is a set of the form (x,y,z,w)

Lagrange's Four Squares Theorem

PDF) Quarternions and the Four Square Theorem

Waring's Problem & Lagrange's Four-Square Theorem

Sum of squares, Part-2, Sum of four squares