>>> from seqrac import sequencia

---ini-enunciat

>>> it = sequencia(3)
>>> next(it)
Fraction(1, 3)
>>> next(it)
Fraction(9, 2)
>>> next(it)
Fraction(19, 7)
>>> for i in range(10):
...    print(next(it), end=",")
39/22,79/67,159/202,101/53,203/160,11/13,39/22,79/67,159/202,101/53,

---fi-enunciat

>>> it = sequencia(17)
>>> for i in range(10):
...    print(next(it), end=",")
1/17,51/2,103/7,207/22,415/67,831/202,1663/607,3327/1822,605/497,1211/1492,

>>> it = sequencia(112)
>>> for i in range(10):
...    print(next(it), end=",")
1/112,168,337/4,675/13,1351/40,2703/121,5407/364,10815/1093,21631/3280,43263/9841,