If this format is consistent, then...
1) Select Column B (for the relevant range), and then ctrl-drag and drop it on column F to create a copy of the values in Column B.
2) Drag and drop that copy upwards by one row (not a copy - move it) - this will leave you with the first and every second row after that looking like you want, with the other rows containing the Key value and the related name.
3) Sort the whole range by Column B - the numeric values will move to the top or bottom (depending on whether you are sorting ascending or descending - it really doesn't matter) , with the alphabetic values going the other way - you want to keep the rows with numeric values.
4) Go to the top or bottom of the sorted range, select the rows with alphabetic entries in Column B, and delete them.
5) Re-sort the remaining list in whatever order is best suited for your task.
6) If you want to return to the order shown, before you perform the sort in step 3 add a sequence number to each record, and then run the step 5 sort on that sequence number.