expansion_square.py

param = int(input('Enter a number: '))
line_length = (param * 2) - 1
for i in range(param + 1)[::-1]:
    multiplier = ((i * 2) - 1)
    center_string = str(i) * multiplier
    if multiplier < line_length:
        sides = []
        for ii in range(i + 1, param + 1):
            sides.append(str(ii))
        
        if i != 0:
            print('%s%s%s' % (''.join(sides[::-1]), center_string, ''.join(sides)))
        else:
            for ix in range(2, param + 1):
                multiplier = ((ix * 2) - 1)
                center_string = str(ix) * multiplier
                if multiplier < line_length:
                    sides = []
                    for ii in range(ix + 1, param + 1):
                        sides.append(str(ii))
                    
                    print('%s%s%s' % (''.join(sides[::-1]), center_string, ''.join(sides)))
                else:
                    print(center_string)   
            
        
    else:
        print(center_string)