scipy.signal._filter_design:_bessel_poly

Extended Summary

If reverse is true, a reverse Bessel polynomial is output.

Output is a list of coefficients: [1] = 1 [1, 1] = 1*s + 1 [1, 3, 3] = 1*s^2 + 3*s + 3 [1, 6, 15, 15] = 1*s^3 + 6*s^2 + 15*s + 15 [1, 10, 45, 105, 105] = 1*s^4 + 10*s^3 + 45*s^2 + 105*s + 105 etc.

Output is a Python list of arbitrary precision long ints, so n is only limited by your hardware's memory.

Sequence is http://oeis.org/A001498, and output can be confirmed to match http://oeis.org/A001498/b001498.txt :

>>> from scipy.signal._filter_design import _bessel_poly
>>> i = 0
>>> for n in range(51):
...     for x in _bessel_poly(n, reverse=True):
...         print(i, x)
...         i += 1