Convert number-ranges to sequence of numbers (e.g. 142-145 to 142, 143, 144, 145)

Thank you again macropod and thank you jindon!
At the moment I can understand jindons code better. Two problems, though:
1) A "single" number will not have an output, e.g. "12" will not be converted to "12"
2) I can't adapt the code from a single row (e.g.: "b3") to a "matrix" (e.g.: "b3:c5"), i.e. I don't know how to add additional rows to the code

TIA!