Phase 3 of the GSoC coding period is traversong smoothly. !! I and Sartaj had a meeting on the 05th of August, about the timeline of the next 2 weeks. Here are the deliverables that have been completed in this week, including the minutes of the meeting.
 The second
aseries
PR #17303 has been implemented. I have implemented theeval_aseries()
functions for several special functions. Here are the list of those functions.
erf: gauss error function
erfc: complementary error function
erfi: imaginary error function
Ei: exponential integral
expint: generalised exponential integral
li: logarithmic integral
Li: offset logarithmic integral
Si: sine integral
Ci: cosine integral
bessely
besselj
lerchphi function
Riemann zeta function
To show you some glimpses of the implementation, I have written the _eval_aseries()
function for erf
and erfc
functions. They are as follows 
def _eval_aseries(self, n, args0, x, logx):
from sympy.series.order import Order
point = args0[0]
if point is S.Infinity:
z = self.args[0]
s = [(1)**k * factorial2(2*k  1) / (z**(2*k + 1) * 2**k)
for k in range(0, n)] + [Order(1/z**n, x)]
return S.One  (exp(z**2)/sqrt(pi)) * Add(*s)
return super(erf, self)._eval_aseries(n, args0, x, logx)
def _eval_nseries(self, x, n, logx):
nu, z = self.args
if z.limit(x, 0) is S.Zero:
s = [(1)**k * z**(2 * k) / (factorial(k) * factorial(nu + k) * 2**(2 * k))
for k in range(0, n)] + [Order(z**n)]
return (z/2)**nu * Add(*s) # removeO fails
return super(besselj, self)._eval_nseries(x, n, logx)
This PR is now open for reviews. Once the first PR gets mereged, the tests for these PRs can pass then.

The first
aseries
PR #17167 is ready for merging. Sartaj had requested some changes regarding thedocstring
of theaseries
function, and some other changes. All those changes have already been integrated. 
There have been changes requested in the
class
PR #17134 as well. They have also been changed.
Thatâ€™s it for this week. See you in the next week and the last phase. Till then, Adios!!