Deleting rows in a columns of numbers with increment '1' shows "#REF" How to pick up the above cell

PruJakkam 

Yes, it would, wouldn't it?  I have been bitching for a decade about the appalling practices of traditional spreadsheets, such as the idea of relative references (to scan lists and arrays) and the garbage idea of referencing data by it location (A1 notation) rather than its content (named).  I couldn't think of a more error-prone strategy.  The surprise for me was that auditing shows only 90% of workbooks to be in significant error; I might have expected a higher figure. 

OK, that's the rant over!  It wasn't aimed at you; I just don't like the normal spreadsheet practice with its hard-to-memorise 'tips and tricks'.  Before 2018, I was stuck with what I was given and one way of dealing with the problem you outline is to use a defined name to reference the cell above

above "(defined with cell A2 active)"
= Sheet1!A1

or rather less ambiguously with the R1C1 notation

above
= Sheet1!R[-1]C

 Since there is only a single definition of the name, it cannot track individual cells, so you get what it says on the tin!  Of course, now I would simply use

= SEQUENCE(20)

and the problem no longer exists!