Using hash tag (#) in a reference

I've deduced that in a formula such as sum(A6#) the A6# will refer to the range from A6 to the last cell in the array formula that governs the contents of A6. It does not work unless column A has an array formula in it. Using this syntax is super handy when the number of rows that I'm referencing is unknown.
My question is whether there is a similar syntax for referencing everything to the last column of a row array. For example, I have sum(A$7:Y$7) but I really want something like sum(A#$7) to sum to the last column in the array, rather than having to fix it at column Y.
Thanks!

PS. Any way to get the reCAPTCHA on this post editing page to stop timing out every 30 seconds or so...even when I'm typing?

Thank you 6StringJazzer, for making me create a sample file. In so doing, I realized the problem - the range I was trying to reference with the # was not, in fact, an array formula. And, for whatever reason, as I compose this reply, there is no reCAPTCHA verification. Maybe I wasn't logged in properly before?