Column A contains only unique value.
I have actually achieved this using two formulas:
(i) Arrayformula at B1:
={"ARRAYFORMULA 1";ARRAYFORMULA(if($A2:$A = "",,countifs(countifs($A2:$A, $A2:$A, row($A2:$A), "<=" & row($A2:$A)), 1, row($A2:$A), "<=" & row($A2:$A))))}
(ii) Formulas at column B:
=INDEX(FILTER(B$1:B2,B$1:B2<>""), COUNTA(FILTER(B$1:B2,B$1:B2<>"")))
(1) Why doesn't Arrayformula version of this formula doesn't work:
=Arrayformula(INDEX(FILTER(B$1:B2,B$1:B2<>""), COUNTA(FILTER(B$1:B2,B$1:B2<>""))))
(2) I am not able to get a single Arrayformula to produce my result. What Arrayformula should I use at D1 to my desired results?