gistfile1.py

In [21]: res = 0

In [22]: for i, element in enumerate(x):
    res |= element << i*4
   ....:     

In [23]: res
Out[23]: 1048575

In [24]: hex(res)
Out[24]: '0xfffff'

In [25]: x
Out[25]: [15, 15, 15, 15, 15]

In [26]: [hex(e) for e in x]
Out[26]: ['0xf', '0xf', '0xf', '0xf', '0xf']