C# - Retrieve Not Empty Rows In First Column Of Excel Sheet

My requirement is to read all rows of an excel-sheet in first column that are not empty, are numeric and have a length between 15 and 20.

For example:
358218033354974
359473035499561
358218036156129
354022038366247
358218032490035
359473030516492
353210040325399

This column might have a header that is not numeric and there might be empty rows. This would cause an exception when importing them via SqlBulkCopy. So i want to prefilter the correct rows via OleDbCommand.

What I have tried so far is following(C# is also appreciated):
Using connection As New OleDbConnection(sExcelConnectionString)
connection.Open()
Dim schemaTable As DataTable = _
connection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, _
New Object() {Nothing, Nothing, Nothing, "TABLE"})
[Code] .....

But this throws an exception if there are empty rows or the format of the value is incorrect. So my question is: How to restrict the rows of OleDbCommand to:
Get only first column of every worksheet
All values that are numeric
Skip empty values
Ideally only the values with a length between 15 and 20

Any way how to skip the empty rows, Or do I have to to select the whole datatable? I hoped it would be possible to do that only with one query because of performance reasons.