simple series interpolation

Hello everyone, I want to use a formula to do some very simple linear interpolations (which I will later enter into a macro to auto search for and interpolate blank cells). Thank you in advance!

The formula should be able to take these numbers in a column:

1
2
(empty cell)
(empty cell)
(empty cell)
6
7

And fill in the blanks to create this series in another column:

1
2
3
4
5
6
7

The formula should be able to do this if there is one empty row, or more.

If there is just one empty cell, I know I can use the following formula, but when I tried creating nested IF statements to account for multiple empty cells, I had a lot of trouble: =X78-X78-X80)/(ROWS(X78:X80)-1)

Thank you!

Thank you Palmetto. I'm good now thanks to this link: http://excel.bigresource.com/Track-excel-dbXbI4ga/

It uses VBA instead of a simple formula, but that's probably for the best.