Integer as Sum of 5 Non-Zero Squares

Theorem
Let $n \in \Z$ be an integer such that $n > 33$.

Then $n$ can be expressed as the sum of $5$ non-zero squares.

Proof
From Lagrange's Four Square Theorem, every positive integer can be expressed as the sum of $4$ squares, some of which may be zero.

The existence of positive integers which cannot be expressed as the sum of $4$ non-zero squares is noted by the trivial examples $1$, $2$ and $3$.

Thus Lagrange's Four Square Theorem can be expressed in the form:
 * $(1): \quad$ Every positive integer can be expressed as the sum of $1$, $2$, $3$ or $4$ non-zero squares.

We note the following:

Let $n > 169$.

Then $n$ can be expressed as:
 * $n = m + 169$

where $m \ge 1$.

From $(1)$, $m$ can be expressed as the sum of sum of $1$, $2$, $3$ or $4$ non-zero squares.

Thus at least one of the following holds:
 * $m = a^2$
 * $m = a^2 + b^2$
 * $m = a^2 + b^2 + c^2$
 * $m = a^2 + b^2 + c^2 + d^2$

Thus one of the following holds:

It remains to be shown that of the positive integers less than $169$, all but the following can be expressed in this way:
 * $1, 2, 3, 4, 6, 7, 9, 10, 12, 15, 18, 33$

First we show the ones which can: