5.38.1 Definition : seq[] ()
A sequence is represented by
a sequence of elements separated by commas, without
delimiters or with either ( ) or seq[...]
as delimiters, for example
(1,2,3,4)
seq[1,2,3,4]
Input :
A:=(1,2,3,4) or A:=seq[1,2,3,4]
B:=(5,6,3,4) or B:=seq[5,6,3,4]
Remarks

The order of the elements of the sequence is significant.
For example, if B:=(5,6,3,4) and C:=(3,4,5,6), then
B==C returns 0.
 (see also 5.38)
seq([0,2])=(0,0) and seq([0,1,1,5])=[0,0,0,0,0] but
seq[0,2]=(0,2) and seq[0,1,1,5]=(0,1,1,5)