In[]:=
points={{0,0},{1,1},{2,3},{3,4},{4,3},{5,0}};
In[]:=
func=Interpolation[points]
Out[]=
InterpolatingFunction
Domain: {{0,5}}
Output: scalar
Order: 3
Method: Hermite
Periodic: False

In[]:=
func//InputForm
Out[]//InputForm=
InterpolatingFunction[{{0, 5}}, {5, 3, 0, {6}, {4}, 0, 0, 0, 0, Automatic, {}, {}, False}, {{0, 1, 2, 3, 4, 5}}, {{0}, {1}, {3}, {4}, {3}, {0}},
{Automatic}]
In[]:=
func//FullForm
Out[]//FullForm=
InterpolatingFunction[List[List[0,5]],List[5,3,0,List[6],List[4],0,0,0,0,Automatic,List[],List[],False],List[List[0,1,2,3,4,5]],List[List[0],List[1],List[3],List[4],List[3],List[0]],List[Automatic]]