Replace all __ with rjust, ljust or center.

thickness = int(input()) #This must be an odd number c = 'H'

Top Cone

for i in range(thickness): print((c*i).rjust(thickness-1,' ')+c+(c*i).ljust(thickness-1, ' '))

Top Pillars

for i in range(thickness+1): print((c*thickness).center(thickness*2, ' ')+(c*thickness).center(thickness*6, ' '))

Middle Belt

for i in range((thickness+1)//2): print((c*thickness*5).center(thickness*6, ' '))

Bottom Pillars

for i in range(thickness+1): print((c*thickness).center(thickness*2, ' ')+(c*thickness).center(thickness*6, ' '))

Bottom Cone

for i in range(thickness): print(((c*(thickness-i-1)).rjust(thickness, ' ')+c+(c*(thickness-i-1)).ljust(thickness, ' ')).rjust(thickness*6, ' '))