>>> from series11 import calc_term

--ini

>>> x = calc_term(0.1, 0.1, 4.0)
>>> x
0.2201

>>> x = calc_term(0.1, 0.1, x)
>>> x
0.1557

>>> x = calc_term(0.1, 0.1, x)
>>> x
0.1256

--fi

>>> x = calc_term(0.0, 0.0, 0.0)
>>> x
0.0

>>> x = calc_term(-1.0, 1.0, 0.0)
>>> x
0.5

>>> x = calc_term(-1.0, 1.0, x)
>>> x
0.1579

>>> x = calc_term(-1.0, 1.0, x)
>>> x
0.3598

>>> x = calc_term(-1.0, 1.0, x)
>>> x
0.2261