[THOUGHT] Analyzing the problem, we consider Levenshtein distance in $\mathbb{Z}_2^{100}$ for radius $1$. With 100 dimensions and radius $1$, the maximal sphere involves the center and all vectors at Hamming distance $1$. Substituting any single bit yields 100 neighbors, plus the center totaling $101$. [/THOUGHT] [PYTHON]

Compute the max size assuming center and Hamming neighborhood of radius 1

ans = 1 + 100
print(ans)
[/PYTHON]

$\boxed{101}$[THOUGHT] Analyzing the problem, we consider Levenshtein distance in $\mathbb{Z}_2^{100}$ for radius $1$. With 100 dimensions and radius $1$, the maximal sphere involves the center and all vectors at Hamming distance $1$. Substituting any single bit yields 100 neighbors, plus the center totaling $101$. [/THOUGHT] [PYTHON]

Compute the max size assuming center and Hamming neighborhood of radius 1

ans = 1 + 100
print(ans)
[/PYTHON]

$\boxed{101}$

[THOUGHT] The Python output confirms the maximum size of the ball of radius 1 in $\mathbb{Z}_2^{100}$ is 101. This includes the center vector and its 100 neighbors with exactly one differing bit. Validation via computation validates direct combinatorial reasoning. No further steps necessary. [/THOUGHT] $\boxed{101}$[THOUGHT] The Python output confirms the maximum size of the ball of radius 1 in $\mathbb{Z}_2^{100}$ is 101. This includes the center vector and its 100 neighbors with exactly one differing bit. Validation via computation validates direct combinatorial reasoning. No further steps necessary. [/THOUGHT] $\boxed{101}$