Hi Greg,
I created a sample to put a formula in a cell on each row created from the population of an excel from a DataTable. Here is the sample for your reference:
http://websamples.syncfusion.com/samples/XlsIO.Web/4.4.0.51/61332/main.htmNote:
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Please use R1C1 and not L1C1
Please take a look at the sample above and kindly let me know if this helps you.
Thanks,
Melba