I am needing to find a way to 'extend a series' for an entire column with
multiple numbers without having to extend each series individually.

Here's basically what I have: Here's what I need it to look like:

345 345
(blank cell) 345
(blank cell) 345
(blank cell) 345
675 675
(blank cell) 675
(blank cell) 675
987 987
(blank cell) 987
(blank cell) 987
(blank cell) 987

Right now I'm have to click each number to get it to extend the series down
to the next number. Typically this wouldn't be a big hassel to do them
individually, but I'm now dealing with over 1,400 numbers and doing this
individually all the way down the column is very time consuming and making me
crazy! Does anyone have any suggestions? Thank you for any input!