​​Foundat​​https://mathworld.wolfram.com/Erf.html
In[]:=
c=
π
2
(Normal[Series[Erf[z],{z,0,10}]]);
In[]:=
2
π
Simplify[c]
Out[]=
2z-
3
z
3
+
5
z
10
-
7
z
42
+
9
z
216
π
In[]:=
WolframAlpha["{3, 10, 42,216}",{{"PossibleContinuationFromOEIS",1},"ComputableData"}]
Out[]=
OEIS A007680
In[]:=
2
π
∞
∑
n=0
n
(-1)
2n+1
z
(2n+1)*n!
Out[]=
Erf[z]
In[]:=
2
π
∞
∑
n=0
2n+1
z
(2n+1)*n!
Out[]=
Erfi[z]