Hailstone sequence in Cython

hailstoneCython.pyx

"""Hailstone sequence.
"""

# compile with
# cython hailstoneCython.pyx
# -O2 -shared -fPIC -march=native  -IPATH_TO_PYTHON.H -o hailstoneCython.so hailstoneCython.c

cpdef list hailstone(int n):
    cdef list seq
    seq = [n]
    while n>1:
        n = 3*n + 1 if n & 1 else n//2
        seq.append(n)
    return seq