LAMBDA : function generating #NAME error

I'm not sure what your issue is.  What do you mean when you say "I debug the cell"?  I tried you LAMBDA 3 different ways and it worked in each case:

column E has the formula and column F shows the formula so

the first row is LAMBDA inline with no assignment just the variables directly passed in

the second row combines with the LET function to assign it to _gilles and then pass the variables into it

the third row uses the Name Manager (as shown in the name manager window below it) to define the function and then just calling the function with the varibles.

Maybe give us more information.  Is the problem the variable/number you are passing into it?

I also just tried it using Excel Labs and entered it as a Function in the Names tab and also as function in the Modules tab and again no issues.