A sequence is a series of elements that can be enumerated. It is an alias of System.Collections.Generic.IEnumerable and lazy. It stores a series of elements of the same type (can be any value or object, even another sequence). Functions from the Seq.module can be used to operate on it.
Here is a simple example of a sequence enumeration:
let mySeq = { 0..20 } // Create a sequence of int from 0 to 20
mySeq
|> Seq.iter (printf "%i ") // Enumerate each element of the sequence and print it
Output:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20