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Lego Small Blocks

Lego Small Blocks
What is the smallest number of cubes in a lattice that cannot be enclosed by a sphere without enclosing more?

Imagine that I have cubical lego blocks. Is it possible to have n cubes such a way that they cannot be stacked together and fit inside a sphere, and no MORE cubes can be stacked within it? If that's possible, what's the smallest n for which this is true?
For example, 2x2x2 = 8 can be enclosed by a sphere without room for another. Is there a number n that cannot be enclosed by a sphere without leaving room for at least one more? All possible arrangements of stacking n cubes are to be considered.
To make this problem simpler, all the cubes fit within a lattice, face to face.
7 cubes isn't it because they can be stacked in a cross formation so that the sphere that just encloses them doesn't have room for any more.
The answer is 3 cubes. This problem gets easier with very small n. Maybe I should be asking if there is an upper limit for n?
There are only 2 ways 3 cubes can be stacked, all in line or in a L. The smallest sphere enclosing either one leaves room for at least one more.

Is a cube considered a cross formation?

3*3*3 -(1 in the middle), corners facing? 26 total.

If you start stacking them horizontally and the foundation would be: 1,2,3,10,11,12,19,20,21

The middle row: 4,5,6,13,22,(nonexistent)24

Top row:7,8,9,,16,17,18,25,26,27

Nonexistent lays between 11,13,15 and 17

Edit:
I do not get it!
I assumed that the sphere was a perfect cube and had to be even.

But now I do understand why the 3 other brilliant answerers that starred your question did not answer it yet.

I guess your question is more complicated than I assumed.
Sorry about that.

Please explain how can it 3?