Actually, technically:
ROW(A1:A6)
returns:
{1;2;3;4;5;6}
not:
{1,2,3,4,5,6}
though for the purpose of this exercise this is unlikely to be of relevance.
However, in general, ROW(A1:A6) is not a very rigorous choice, since any row insertions within the range will most likely lead to errors here.
Better is:
ROW(INDEX(A:A,1):INDEX(A:A,6))
which gives:
{1;2;3;4;5;6}
or, if vector-type is a concern:
COLUMN(INDEX(1:1,1):INDEX(1:1,6))
which gives:
{1,2,3,4,5,6}
both of which are immune to row/column insertions within the worksheet (though the latter cannot create arrays containing more than 16,384 entries - for that it would be necessary to employ ROW and then transpose the resulting array).
Regards