SUMSQ for summing the inverse of a series of squared numbers

Here is the forrmula I want to solve. I could do this by adding another coulmn but I am trying to keep the sheet simple in appearance and easily allow the addition of more rows to be included in the sum.

=( 1/(x₁)² + 1/(x₂)² + 1/(x₃)² + ...

So for a range of cells containing 1,2 and 3, the correct answer is 1.36111.

My test range of values is K40 to K43 and I have tried:
=SUMSQ((K40:K42)^-1) and =SUMSQ(1/(J40:J42)) and both give #VALUE in the cell.

The odd thing is that when I click on the Excel fx button to get function guidance for either of the formulas that I have tried,the correct answer is provided in the popup window. But when I click OK, I get "#VALUE" in the cell.

Can someone help with this?

EM.