You can write $2023$ as the sum of four squares ($61$ ways) using any row of the following table.
$$\left(
\begin{array}{cccc}
1 & 2 & 13 & 43 \\
1 & 5 & 29 & 34 \\
1 & 7 & 23 & 38 \\
1 & 10 & 31 & 31 \\
1 & 11 & 26 & 35 \\
1 & 13 & 22 & 37 \\
1 & 17 & 17 & 38 \\
2 & 5 & 25 & 37 \\
2 & 7 & 11 & 43 \\
2 & 7 & 17 & 41 \\
2 & 11 & 23 & 37 \\
2 & 13 & 13 & 41 \\
2 & 13 & 25 & 35 \\
2 & 17 & 19 & 37 \\
2 & 23 & 23 & 31 \\
3 & 3 & 18 & 41 \\
3 & 3 & 22 & 39 \\
3 & 5 & 15 & 42 \\
3 & 5 & 30 & 33 \\
3 & 9 & 13 & 42 \\
3 & 13 & 18 & 39 \\
3 & 14 & 27 & 33 \\
3 & 18 & 27 & 31 \\
3 & 21 & 22 & 33 \\
5 & 5 & 23 & 38 \\
5 & 6 & 21 & 39 \\
5 & 7 & 10 & 43 \\
5 & 10 & 23 & 37 \\
5 & 11 & 14 & 41 \\
5 & 14 & 29 & 31 \\
5 & 17 & 22 & 35 \\
5 & 19 & 26 & 31 \\
6 & 9 & 15 & 41 \\
6 & 13 & 27 & 33 \\
6 & 23 & 27 & 27 \\
7 & 11 & 22 & 37 \\
7 & 13 & 19 & 38 \\
7 & 17 & 23 & 34 \\
7 & 22 & 23 & 31 \\
9 & 9 & 30 & 31 \\
9 & 14 & 15 & 39 \\
9 & 18 & 23 & 33 \\
9 & 22 & 27 & 27 \\
10 & 11 & 11 & 41 \\
10 & 11 & 29 & 31 \\
10 & 13 & 23 & 35 \\
11 & 11 & 25 & 34 \\
11 & 13 & 17 & 38 \\
13 & 13 & 23 & 34 \\
13 & 14 & 17 & 37 \\
13 & 15 & 27 & 30 \\
13 & 18 & 21 & 33 \\
13 & 22 & 23 & 29 \\
14 & 19 & 25 & 29 \\
15 & 15 & 22 & 33 \\
17 & 17 & 17 & 34 \\
17 & 17 & 22 & 31 \\
17 & 22 & 25 & 25 \\
17 & 23 & 23 & 26 \\
18 & 21 & 23 & 27 \\
19 & 19 & 25 & 26 \\
\end{array}
\right)$$
For example, using the first row, we have
$$2023 = 1^2 + 2^2 + 13^2 + 43^2$$
Another
How many solutions does the following have?
$$20 x_1 +23 x_2 =2023$$
We have
$$(x_1, x_2) = (8, 81), (31, 61), (54, 41), (77, 21), (100, 1)$$
Another
$2023$ as the sum of five cubes (I think it is the only one)
$$2023 = 2^3+5^3+6^3+7^3+11^3$$
Another
Write $2023$ as the sum of Fibonacci numbers ($18$ ways)
$$\begin{array}{l}
1597+377+34+13+2 \\
1597+377+34+8+5+2 \\
1597+233+144+34+13+2 \\
987+610+377+34+13+2 \\
1597+377+21+13+8+5+2 \\
1597+233+144+34+8+5+2 \\
1597+233+89+55+34+13+2 \\
987+610+377+34+8+5+2 \\
987+610+233+144+34+13+2 \\
1597+233+144+21+13+8+5+2 \\
1597+233+89+55+34+8+5+2 \\
987+610+377+21+13+8+5+2 \\
987+610+233+144+34+8+5+2 \\
987+610+233+89+55+34+13+2 \\
1597+233+89+55+21+13+8+5+2 \\
987+610+233+144+21+13+8+5+2 \\
987+610+233+89+55+34+8+5+2 \\
987+610+233+89+55+21+13+8+5+2 \\
\end{array}$$
Another
$$2023 = MMXXIII$$