The spreadsheet widget supports array formulas with a manual Ctrl-Shift-Enter. (see bottom of https://docs.telerik.com/kendo-ui/controls/data-management/spreadsheet/end-user/list-of-formulas)
I want to do the same programmatically using the Spreadsheet.Model classes.
This example shows how I can set and get results of a simple calculation, however the array formula I want to use is an Error.
Indeed, the Sample.xlsx it creates, when opened shows #N/A where the array formula is. However, in Excel, when I edit the cell and do Ctrl-Shift-Enter, it is interpreted as an array formula and shows the proper result. The same formula in the spreadsheet widget also works (kudos to the dev team -- array formulas can make you squirrely).