Color fill rows based on dupe value

I need to color fill rows in a spreadsheet based on account number so I can easily distinguish them. for example, my data might be like:

acct # 1
acct # 1
acct # 1
acct # 2
acct # 2
acct # 3
acct # 3

I would want rows w/ acct # 1 to be colored differently than acct # 2, but 1 and 3 could be the same color, as long as it could change dynamically.

If anyone could help, it would make my life much easier.

Thanks,

Jay

Close, but not quite.

This would work if the number of rows with dupe acct numbers were equal, but in my case, there could be 1 account number, or 10 duplicates.

Esssentially it would need to somehow look at the account number, compare it to the surrounding cells, and fill it with the same color as the cell above it (if the account number is equal) or fill it with a different color (if not equal).

Thanks for the help,

Jay

I would use a helper column that indexes the groups of accounts. This index increases by one for each new account.
I then use conditional formatting to check if this index number is odd or even and make a different color for the even numbered indexes.

You can hide the helper column

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