Libre Office Calc copy and doubles values to other column

Question

i have in Libreoffice Calc column A eg

1
5
25
7

and i want create column B with some copy method to

1
1
5
5
25
25
7
7

it has to be some simple solution, but i dont find it :(

thanks for answer

Answer just under this question is for Excel, but i need for LibreOffice Calc (my fault, i ask for excel earlier)

Answer 1

To adapt Scott Craner's answer for LO Calc, the formula in B1 should be:

=INDEX(A:A,INT((ROW()-1)/2)+1)

Or this:

=INDIRECT(ADDRESS(INT((ROW()-1)/2)+1,1))

Documentation: INDEX, INDIRECT, ADDRESS, ROW.