Sums of Squares/Mistake/Second Edition

Source Work

1994: Richard K. Guy: Unsolved Problems in Number Theory (2nd ed.):

$\mathbf C$: Additive Number Theory

$\mathbf {C 20}$: Sums of Squares

Mistake

Apart from $256$ examples, the largest of which is $1167$, every number can be expressed as the sum of at most five composite numbers.

Correction

It should say:

Apart from $256$ examples, the largest of which is $1167$, every number can be expressed as the sum of at most five squares of composite numbers.

(emphasis added)

This has been corrected for Unsolved Problems in Number Theory, 3rd ed..

Also see

• Numbers Not Expressible as Sum of no more than $5$ Squares of Composite Numbers

Sources

• 1994: Richard K. Guy: Unsolved Problems in Number Theory (2nd ed.): $\mathbf C$: Additive Number Theory: $\mathbf {C 20}$: Sums of Squares