Increment x in Col A ONLY IF adjacent Col B cell NOT Blank

[powerjak]

Should be simple, but I'm in a brain-lock. I want to increment by 1, a value in Column A successive row cells, but only IF the adjacent cell in Column B is NOT blank. IF Column B cell ISBLANK(), then Column A cell is to also be blank.

Example:

A B
1 text
2 text
3 text
4 text

5 text
6 text

7 text

I've tried a number of nested IFs using different Fx evaluations of Col B, but so far, nothing I've tried gets me a result that I can replicate down all row cells of Col A to get the results of the example above without any error results.

I'm sure it'll turn out to be a "head slapper" when one of you bright people provide the assist to untwist my brain ... and I'll certainly appreciate the help!

 

[KenWright]

OK Cheers