I'm too tired to xml out of gnumeric to google,
so the formulas are:
=year(today()) ....................aka b15, for the year date
=(E13*$H$9)*10 ....................for the # of yrs
where e13 is the generation number and and h9 is 3
=$B$15-(E13*30) .................. where b15 is the year,
and e13 is the generation number.
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