PadeApproximant
PadeApproximant[expr,{x,x0,{m,n}}] gives the Padé approximant to expr about the point x=x0, with numerator order m and denominator order n.
PadeApproximant[expr,{x,x0,n}] gives the diagonal Padé approximant to expr about the point x=x0 of order n.
Please visit the official Wolfram Language Reference for more details and examples on core symbols.