Numbers not Expressible as Sum of Fewer than 19 Fourth Powers/Historical Note

Historical Note on Numbers not Expressible as Sum of Fewer than 19 Fourth Powers
It was noted by that there are no other positive integers less than $4100$ needing $19$ fourth powers to express them.

This limit was reported by in his  of $1986$.

, and  extended this to $10^{245}$ in $2000$.

In $2005$,, and  showed that the sequence is complete beyond $10^{220}$.