program exampleSerial
implicit none
INTEGER :: loop1Indx, loop2Indx, loop1Limit, loop2Limit
loop1Limit=20
loop2Limit=5
do loop1Indx = 1, loop1Limit
do loop2Indx = 1, loop2Limit
write(*,*) loop2Indx+(loop1Indx-1)*loop2Limit
enddo
end program