Function: mfEk
Section: modular_forms
C-Name: mfEk
Prototype: L
Help: mfEk(k): mf corresponding to the standard Eisenstein series
 E_k for nonnegative even integer k.
Doc: k being an even nonnegative integer, return the mf structure
 corresponding to the standard Eisenstein series $E_k$.
 \bprog
 ? mfcoefs(mfEk(8), 4)
 %1 = [1, 480, 61920, 1050240, 7926240]
 @eprog
